The body is subjected to physical pain due to aging, disease, environmental conditions, and so on. Every person in the world has experienced physical pain. There is no way to get rid of pain permanently no matter how medically advanced we become. The only way to deal with pain is to manage it and to make the body pain- transcendent (and not pain-free). A pain-transcendent body is an intelligent body.
Pick any physical activity or exercise and, as you perform it, begin to notice how your body is subjected to stretching, straining, and resistance from gravity, because of which unpleasant feelings of discomfort or exertion arise. Become mindful of unpleasant feelings in the body, as they always arise before the advent of pain. Note that unpleasant feelings become pain only when you develop an aversion to them, meaning, only when you react to their unpleasantness. So, in order to distinguish between unpleasant feelings and pain, remain aware of the degree of aversion—in other words, your mood during the practice.
Once you notice unpleasant feelings, observe them without reacting. Do not suppress or fight the unpleasantness. Simply observe it as it arises during a prolonged state of physical activity. Notice how unpleasantness eventually ceases due to mindfulness of unpleasantness and non-reaction to it. Also notice how it aggravates and eventually turns into physical pain if you react or try to resist it. In other words, try to realize that unpleasantness itself is not necessarily pain. It becomes pain only when you react, resist, or fight it. Also, realize that when you let go of unpleasantness it ceases to control the mind and does not result into pain.
Now, apply wise attention to your feelings of unpleasantness and try to understand experientially that the degree of unpleasantness and your reaction to it is directly proportional to your attachment to the body—to your attachment to the memory of past experiences of pleasant feelings in the body. In this way, first understand pain experientially as a reactive state of mind arising from the experiencing of unpleasant as well as pleasant feelings in the body. Then, start observing all pleasant bodily feelings without liking them and all unpleasant feelings without disliking them. In this way, start eradicating deep-rooted craving and aversion, and develop equanimity towards bodily feelings.
Also, learn how to increase your tolerance towards unpleasantness. Start any physical activity or an exercise of your choice. Slowly increase your physical efforts or the intensity of your workout only up to the limit where you can maintain equanimity towards unpleasantness. You want the unpleasantness just to begin being aggravated, but not to reach the level of physical pain. In this way, find out your current boundaries of the comfort zone or physical tolerance and expand or increase it intelligently without subjecting yourself to outright pain.
In subsequent workouts, as stamina and strength increases along with equanimity,