what I've found is "arthritis" doesn't cause pain. It is what arthritis causes to happen which causes the pain. You may have gout. Try a low-purine diet. Also get a simple blood test for high uric acid. If it is different than normal possible you have gout arthritis. Take Zazzee Tart Cherry Capsules on Amazon. See if you notice a difference.
You could also try upping your B vitamins with iron to see if you can control the pain which may be caused by the nerve sheaths becoming inflamed. I found both of those my problem. You didn't say what kind of pain you were experiencing? if it feels like rheumatoid but they tell you it's not - then its gout. You don't have to have a gout flare to have gout. I walked around with low-grade inflammation for THIRTY YEARS because I figured out (not the doctors) it was gout. Drs would always say "arthritis." Just arthritis. Because my body is riddled with it. But its not what causes the sensation of pain. THAT was caused by pressure in the joints from inflammation.