How do you know if you have bad/good karma?

It you experience something unpleasant this could partly be due to bad karma. If you experience something positive this can be good karma.

Deciding on your experiences you can see what type of Karma is effective.

Regardless of you being in a positive or negative situation, you have make sure your future is bright, i.e., moving from dark to bright or from bright to brights. You cannot do anything about your current situation but you can do something about the future.

(1) One in darkness faring into darkness, or, from darkness to darkness (karmic stagnation);

(2) One in darkness faring into light, or, from darkness to light (karmic progress);

(3) One in light faring into darkness, or, from light to darkness (karmic descent); and

(4) One in light faring into light, or, from light to light (karmic ascent).

(Tamo,joti) Puggala Sutta

To make your future bright you should stop creating the unwholesome roots, i.e., reacting pleasurable experience with craving or unpleasurable experience with aversion. You should stop this pattern and practice equanimity knowing impermanence.

(1) the latent tendency to lust reinforced by being attached to pleasant feelings;

(2) the latent tendency to aversion reinforced by rejecting painful feelings;

(3) the latent tendency to ignorance reinforced by ignoring neutral feelings.

Pahāna Sutta

That is, when you experience negativities do not react with negativities or aversion, but be equanimous knowing this experience is impermanent.

It is not only you. Everybody have to reap what they sow. Beginningless long samsara that we passed through, all the deeds good or bad just follow you like your own shadow. Even Buddha had these consequences of the long passed samsara. As a Buddhist, true value of triple gem and effect and consequence of karmic result, should be accepted but not blindly. All karma result kaya, versi and manaw done in the past, present and future all have effects. One thing is (huge)good things always have the upper hand over bad ones just like Buddha Dhamma enlighten the darkness of delusion. These present days, if you wish to do/have huge good things, mindfulness in present kaya,versi and manaw act, insight meditation under strong belief in triple gem and karmic effect will only help you. Even large stone that will sink under water can float with the help of large enough boat. Every cloud has a silver lining. To make the most of your misfortune, this is the best time to get enlightened through more concentrated insight meditation reverting all misfortune as your own lesson. As Ledi sayadaw once remind us, just try to loose from the noose when it is time if not you will lost all.

When one does or is still capable of depriving beings from existance, still takes on of what isn't given, still abuses for sense pleasures, still speaks of what isn't true, still takes intoxication and further still has thoughts incl. greed, aversion, confusion, in short who ever hasn't arrived a wrong view, bears still all kind of bad kamma along the way, and just "awaits" it to ripen for a new, without escape.

That's where you are, and it's reasonable to fear, yet possible to change.

[note that this isn't given exchange, trade, stacks, but for liberation from it]

In the Acintita Sutta, the Buddha recommends not to conjecture about kamma due to its complexity.

"There are these four unconjecturables that are not to be conjectured about, that would bring madness & vexation to anyone who conjectured about them. Which four?

...

"The [precise working out of the] results of kamma...

For example, a tree might fall on your house. That could be a result of past kamma, but it might also have nothing to do with your kamma. The weather was bad and the winds were blowing strong, causing the tree to fall over.

Trying to determine if you have good or bad kamma will indeed lead to madness.

How can I change my thoughts to be more positive despite a tremendous amount of negativity in my life?

Know that the negativity is conditioned. Those negative states will cease, as do all conditioned states. Actively practice goodwill, generosity, meditation, and renunciation. It will not take long to see the benefit to your mind as you practice the Buddha's teachings.

The intention (volition or "cetana" in Pali) becomes your kamma as Buddha said in the Nibbedhika Sutta: Penetrative

"Intention, I tell you, is kamma. Intending, one does kamma by way of body, speech, & intellect."

You can apply this to your own life – your past, present & future. For instance you will see inequality in comparing yourself with with your friends and loved ones. In seeing this through Dhamma, Cula-kammavibhanga Sutta: The Shorter Exposition of Kamma will come to mind. Buddha said in this sutta:

"Human beings are owners of kammas, heirs of kammas, they have kammas as their progenitor, kammas as their kin, kammas as their homing-place. It is kammas that differentiate beings according to inferiority and superiority."

This sutta suggest that habitual tendencies of the mind (gathi) play an important role in what you are in your past, present & future. when one thinks, speaks, and bodily acts, a trace of those thoughts, speech, and actions are recorded (like a tape) in the mind plane. On the other hand, the kammic energies associated with a person’s activities are also recorded in the mind plane as kamma seeds having kammic energies associated with them. The real danger in building up bad habits (gathi) is that one could progressively get into worse habits. A teenager who starts drinking could then start using drugs; then it could lead to hanging out with even worse friends and get into drug dealing or even killings. To break away from bad gathi, one needs to make a determination not only to stop such bad activities but also to build up the opposite good gathi, and start heading in the right direction.

If ever you live long, it is due to wholesome kammas before his previous birth unlike that of a person who has engaged in a lot of killing in a past life. However it is important to note that these are guidelines (not rules) and no one can predict the exact destiny of birth of someone. Kamma Vipaka (results) therefore is a very complex subject with many mechanisms in action. Now we can see why Buddha categorized this as a one of the "Acinitita" subjects in Pali.

When you ask How do you know if you have bad/good karma, what you really want to know is, as to "why do bad things happen to good people?" Being a part of this community, you are sure to do wholesome kamma, and rightfully you expect good results in return. If you are a "good person", then you should not get "bad results". However it will not be so. Bad things are sure to come your way. How could this be explained? Again in referring to the scriptures, you will find three types of kamma with regard to the time of their results:

kamma resulting in this life-time (ditthadhamma-vedaniya-kamma), kamma resulting in the next life (upapajja-vedaniya-kamma), kamma resulting in later lives (aparapariya-vedaniya-kamma).

The reason for bad things to happen to good people is not only due to Kamma. It is not the sole determining factor. Buddha's teachings explain that there are five orders or processes (Niyama Dhamma) They are enumerated and defined in the Dhammasaṅgaṇī-aṭṭhakathā:

1. Utu Niyama(Physical-Seasonal changes and climate)
2. Bija Niyama(Biological/Genetic inheritance)
3. Kamma Niyama (Ethical /Consequences of one's actions)
4. Citta Niyama (Psychological/Will of mind)
5. Dhamma Niyama (Laws of nature).

What we can learn from this is that what we experience in life, day in and day out, is the result of a complex interactions of physical, biological, psychological, ethical, or laws of nature. Kamma may play a predominant role, but what ripens is a result of the other four conditions coming together. Therefore kamma is only one of the five factors that come into play when something happens to us, either good or bad.

Very good question.

Some of it is your parents' karma, some is tribal/group karma, some is previous lives karma and then from that, like a branch off of another branch off of trunk, grows your personal karma in this life. So old karma sets the overall direction for new karma, but you can still turn your "twig" in a different direction if you decide.

How do you know which karma is yours from this life and which you inherited from before? You can see in meditation, but more importantly it's all yours in some very important sense: the previous life karma expresses itself through your present karma. However it happened in the past, you are the heir, you are the owner of all that stuff now. Only you can fix it now. So if you get enough inspiration and will power, and enough guidance and insight, you can change your situation and your behavior completely, and start creating completely different karma. Through a combination of suffering (from the fruits of bad karma), luck (encountering true dharma), inspiration (faith), and will or intent (determination to change) - you can change your life completely.

Specifically, to change the thoughts from positive to negative: first you have to set the Right Goal. Then you need to start reviewing all your actions (physical, verbal, and mental - i.e. thoughts!) in light of the goal, and planning your actions -- at least one step in advance -- to make sure they get you closer to the goal, not away from it. And once you keep trying and get better at this, you should look at your actions and congratulate yourself: "look, I am getting better at this". The more you do this, the more it will turn your thoughts from negative to positive.

Hope this helps.

Is it possible to know if you have bad or good karma?

Yes.

A lot of things have happened to me in life that is very negative.

This is normal.

I believe partially it is my own fault because the way I am

It will be your fault when you perform certain actions rather than because of how you are. The phrase "the way I am" has no relevance in Buddhism. What is relevant is the manner & quality of your actions towards others.

and how others preserve of me

Most people are subject to greed, hatred & delusion therefore not all people will view you with friendliness & loving-kindness (metta).

but a lot of it I don't think I deserve.

Often the hatred of others has nothing to do with you therefore it is not related to anything you "deserve".

I often contemplate what did I do to be on the receiving end of all my negative karma.

Your statement here is too general. For example, if your society has social pressures, this can make people, including your parents, inwardly angry.

You should examine or investigate:

1. Your personal actions.

2. The social, political & economic environment of others, which influences their actions.

As a result, I think negative and become very introverted and isolated.

You should learn about what 'skilful karma' is and then examine your own behaviour & the behaviour of others according to what is skilful.

Question: Are all the bad things that happen to me are negative karma or is it "just me"?

The word "karma" means "intentional action". There is no such thing as "past life kamma" affecting your present life. Such ideas are useless superstition & speculations because since you cannot know what you did a past life how can you change what you did in a past life?

The Buddha taught people act with:

1. greed, hatred, delusion & cruelty.

2. friendliness, compassion, equanimity & non-cruelty.

You should learn to examine your own actions and the actions of others based on these criteria to learn if the 'negativity' is caused by you provoking others or caused by the hatred & anger of others or a combination of both.

Today, our world has so many angry & selfish people who are unable to be truly friendly with others. This is related to social, political & economic factors rather than due to intangible speculative ideas about "past life kamma'.

How can I change my thoughts to be more positive despite a tremendous amount of negativity in my life?

As above. You need to start learning about the true Buddhist teachings and find some spiritual friends to help you learn.