What to expect when starting rehab or exercise program?
It’s normal for the pain to increase when starting any rehab or exercise program if you have chronic or persistent pain. This is normal and over time this will improve. Exercise/rehab will decrease the pain over time. It will take time. So stick with it and you’ll get better!
Here’s a nice paper that goes into the mechanism of how exercise works.
Does exercise increase or decrease pain? Central mechanisms underlying these two phenomena