Sorry I really don't know anything about Chron's disease but it looks like you are on some of the same meds taken for RA??? Anyway, I was working with children and came down with a really bad virus but not parvo like we had originally thought, and I started having pain in both of my knees and it just kind of went from there and almost three years later I am still seeing the same rheumy I was referred to in the beginning because my pcp didn't know what was wrong with me.
All of my tests were and still continue to be negative. Although I recently had x-rays to see if I had any signs of rheumatoid in my hands. It took a long time for my doctor to finally diagnose me with RA and you don't have to have labs that are positive, you can have the joint pain and swelling without them. As for the x-rays my fingers are beginning to become crooked/curved but I showed no signs of joint damage.
If you are concerned please ask your doctor, I hope we were of some help to you.