@scottd7 scar tissue within muscle or tight stuck fascia doesn’t usually show up on an MRI. The fascia is a web similar to a spider web that is stretchy and can change shape and reorganize itself. It can get dehydrated and stuck and not move which leads to tightness in muscles and perhaps limits movement. Habits also add to getting stuck if you don’t move enough, for example, sitting too much and not walking may lead to tight hip flexors. I know in my experience with muscle spasms along my spine, it can limit range of motion and cause pain. I had a lot more of that before my spine surgery. My surgical scar does get tight and I need to stretch it out. I can have tightness that extends from my neck through my chest and to my pelvis because of tight fascia. I have learned from my PT how to stretch to help myself function.