It is really important to take your child to a BOARD CERTIFIED PEDIATRIC RHEUMATOLOGIST. Board Certified because it means they have had additional education and testing in the particular discipline and pediatric rheumatologist because children present differently than adults, develop different kinds of arthritis than adults, and handle medications differently. As our pediatric rheumatologist explains it, the sooner you get a child treatment the better they can deal with the effects of the arthritis. If it isn't a form of arthritis, they can tell you.
It can take awhile to get that initial appointment, so make an appointment, and keep it whenever it is. If you want, you can keep calling back to see if there were any cancellations and see if they can slip you in. But put your mind at ease and see the right doctor to diagnose your child.