my rheumatologist says that joint pain is a symptom of whats going on with your ibd/crohn's. it mirrors what is going on in your guts.. so when your joints & such hurt usually your insides have some problems also... ive been having problems with this myself. my rheum says that i may need to go on some biologic with my aza in order to control this, even tho my recent colonoscopy came back clean. he said there may be microscopic inflammation that is not being treated with the aza.