Seeking Advice on Joint Pain and Stiffness

I have been experiencing severe joint pain, stiffness, and soreness. I’ve been in contact with a pediatric rheumatologist over the past few months and we finally found a medication that helps a bit. Anytime I forget to take it, even for just a day, it takes a while of consecutive use to kick back in. I still don’t have any diagnosis for the pain and the medicine I’m on is one that shouldn’t be taken for extended periods of time. I’m just not sure what to do next. The doctor hasn’t really said much so I don’t know what the next steps are.