The people think that karma is metaphysical, but it is not. Karma is a law of nature, like the law of gravity. Karma is part of the physics, of this world. The Vedānta says that you are a soul, not a body. You have a body. The soul (ātman, jīva) is pure in essence; this means that the soul cannot be influenced by anything from nature. In this way, to say that you are suffering the past karma is like to say that this karma has influenced you (a soul). Karma means “action”, if we think about it like a law, we can say: for each action there is a reaction. In this world every action has a reaction and this is not good or bad, it is nature. Karma is not a fate, a fatality. Forget ‘reincarnation’ to talk about karma. First, because the Veda does not speak clearly about it; second because there is not the sense of “re-something” at Sanskrit language. If karma has nothing to do with metaphysics, it means that does not exist “past karma” or “future karma”. What exists is an “ancestry karma”, which is exactly what makes you similar with your parents or family (physical features). When you are born the body that you accept already has a family, with all the characteristics made by the action-reaction law. Karma cannot jail you in this world, because you (soul) are free in essence. Some people say that karma acts in the conscience. It is wrong. Soul and conscience is the same thing (to the Vedānta, at least). So stop to think karma as a metaphysical law. The Vedānta does not put it in this way. We could have a calculus to represent the karma. And could be a simple physical law. If you look at the Bhagavad Gīta (3.5), you will see it written almost like a physical law, saying that karma has your original source in nature (prakṛtijaiḥ).