Interesting question. It's one i've been pondering myself! I think that joint pain from arthritis (OA or RA) CAN be TMS. Arthritis means the wearing away of cartilage in the joint. This is a natural process that occurs as we age. Much like disc herniations, if you did imaging of many people's knees over a certain age, a lot would show arthritis. But many would not complain of pain. Based on reading and experience, I do think a lot of pain people attribute to arthritis is really TMS. CP can certainly cause joint issues...but persistent pain from them is likely TMS and nothing more.