I got them all the time as a kid before my diagnosis and so did my other sister who also has Crohn's. Using a heating pad helped the pain go away. We called them leg aches. I thought they were just growing pains but no one else I've talked to since who doesn't have Crohn's even had them before, least not as often. Crohn's may not be the direct cause but with the inflammation and all that, we don't absorb the nutrients we need and that can cause a bunch of other problems leading to pains like this that we can't quite explain. So in a way, yes its related.