Pain and Exercise
Here is an informative and quick article for the connection between pain and exercise:
It seems counter-intuitive, but science indicates exercise is one of the best ways to reduce pain. Most people I talk to state that exercise causes them pain, so they cannot understand how exercise is supposed to help the pain. There appear to be at least three mechanisms at work when exercise reduces pain. First, people were meant to move. When they stop moving the body starts to hurt. Exercise increases strength and flexibility which reduces pain.
Second, exercise releases chemicals into the body that decrease our sensitivity to pain. There is both a short-term analgesic (pain reducing) effect that happens right after you exercise and a long-term effect where the nervous system actually rewires how you respond to pain over time. This process of rewiring the brain is called neuroplasticity, if you want to go look it up.
Finally, people who exercise for pain reduction unsurprisingly discover that exercise reduces pain. This is an activity broadly referred to as bio-feedback. We do something to our body, pay attention to how it responds, and use this info to adjust how we treat our body in order to get the desired result. People who exercise for pain reduction can experience some amount of control over their pain. Feeling more in control of pain helps people feel less pain and be more able to bear up under the pain they experience.