You surely have a Juvenile RA.Maybe due to this reason you are having seronagative results.Since you already said that your X-Rays shows up badly destroyed joints, this may be a cause of Hyper-Joint mobility.Joint swelling in not always present in these cases.Only when the Arthritis is flared up, we get joint swelling.
So continue as per the doctor's advice and trust his diagnosis.
Keep us informed and posted.
Thank you so much for answering. Just a further question how come joint swelling is not always present? If I don't swell does this mean the arthritis isn't bad? Or does the severity depend more on pain and damage?
This sort of arthritis has a spike pattern.It flares up occasionally.Why-As the stimulus for the flare up of arthritis is not dependent.
The larger the time interval between 2 swelling pattern, the better the situation is dear.