If our present suffering is the result of bad karma from a prior life, what is the real present remedy for suffering in this life?

In order to understand karma and how the concept relates to the Buddhist teachings, one must understand the concept of sankhara. The Pali term “sankhara” is translated as “karma-formations” by Nyanatiloka, the author of Buddhist Dictionary. Another translation could be “schema.” Strictly speaking, sankhara can be understood in two ways:

(1) It can be understood to refer to an unconscious decision-making process that makes use of past experience to select a plan of action (karma) in response to a perceived situation in the present.

(2) It can be understood to refer to a set or system of predispositions that cause this unconscious decision-making process.

Viewed in this way, sankhara is the cause of all intelligent behaviour. The mind consists of a vast number of sankhara(s). A sankhara can be wholesome (kusala), unwholesome (akusala), karma-resultant (vipaka), or functional (kiriya).

All Buddhist practice deals with the various sankhara each of us possess in two ways:

(1) Some practices can be viewed as “coping strategies” that serve the purpose of doing our best while controlling the influence of unwholesome sankhara. The practices of equanimity (upekkha), detachment (tatra-majjhattata), calm (samadhi), and the Eight-Fold Path can be viewed as coping strategies in this sense.

(2) Some practices can be viewed as strategies for undoing or unlearning unwholesome sankhara through recollection (sati) of the historical formation of an unwholesome sankhara.

The practices of mindfulness meditation (satipatthana) and insight meditation (vipassana) can be viewed as strategies that remove unwholesome sankhara that prevent Enlightenment (nibbana; nirvana in Sanskrit).

With this understanding of sankhara, the followings answers can be provided:

Question #1: If our suffering is the result of bad karma from a prior life, what is the real present remedy for suffering in this life?

Answer #1: The premise of this statement is false. Suffering has many causes, some of which are caused by our own unwholesome sankhara(s). Coping strategies mitigate the influence of unwholesome sankhara and thereby constitute a “remedy for suffering in this life,” as does the practice of mindfulness meditation or insight meditation.

Question #2: Can all suffering be alleviated in this life through our efforts with the Eight Fold Path?

Answer #2: No. A lot of suffering is caused by circumstances beyond our control. Following the Eight-Fold Path reduces suffering caused by our own lack of psychological insight.

Question #3: Why engage in any effort related to the Eight Fold Path, if the only true benefits are to be realized in the next life?

Answer #3: The premise of this statement is false. True benefits are realized both in the present life and in the next life.

Can all suffering be alleviated in this life through our efforts with the Eight Fold Path?

Buddha says if you follow the teachings exactly then you will be free of suffering. There is no time limit. It may happen in this life or it may happen after few lives.

Why engage in any effort related to the Eight Fold Path, if the only true benefits are to be realized in the next life?

Even if the benefits are realized in the next life, be thankful because otherwise you would have spent your time taking rebirths, many many rebirths.

If our present suffering is the result of bad karma from a prior life, what is the real present remedy for suffering in this life?

Follow the teachings of Buddha that is do the right thing.

This is not true. Results can be seen in this life itself.

According to the Datthaba Sutta:

Who sees the pain in happiness and views the painful feeling as a thorn, perceives the transience in neutral feeling which is peaceful — right outlook, truly, has such a monk who fully understands these feelings; And having penetrated them, he will be taint-free in this very life. Mature in knowledge, firm in Dhamma's ways, when once his life-span ends, his body breaks, all measure and concept he has transcended.

According to the Akasa Sutta:

But if a monk is ardent and does not neglect To practice mindfulness and comprehension clear, The nature of all feelings will he understand, And having penetrated them, he will be taint-free in this very life. Mature in knowledge, firm in Dhamma's ways, When once his life-span ends, his body breaks, All measure and concept he has transcended.

And what about lay persons who may not be ready for Nibbana?

According to the Appamada Sutta:

For one who desires long life,
health, beauty, heaven, & noble birth, —
lavish delights, one after another —
the wise praise heedfulness
in performing deeds of merit.

When heedful, wise,
you achieve both kinds of benefit:
benefits in this life,
& benefits in lives to come.

By breaking through to your benefit,
you're called
enlightened, wise.

Also please see this answer on how to alleviate the experience of suffering through becoming developed in body and developed in mind.

Present suffering is a result of both past and present Karma. Ex: Physical pain is a result of past Karma, but the mental suffering it causes is a result of being averse to pain. Losing something valuable can be a result of past Karma, but the mental suffering it causes is a result of clinging to it.

The true benefits are realized both now and in the future. But the effort should always be made at the present moment.

Can all suffering be alleviated in this life through our efforts with the Eight Fold Path?

Yes. That's the promise

Why engage in any effort related to the Eight Fold Path, if the only true benefits are to be realized in the next life?

This is a misunderstanding. True benefits are realized now. At the present moment. Anyone who wait for next life or even tomorrow are simply in a state of suffering.

If our present suffering is the result of bad karma from a prior life, what is the real present remedy for suffering in this life?

Non of your suffering is based on bad karma. Suffering is something you do. Not something that happen to you. Enlightened person realize this and stop doing it.

You may have a back pain, which may or may not be karma from past life. But you don't have to suffer it.