I've got severe arthritis on my left kneecap (rest of the joint is fine) and moderate arthritis in my left thumb joint, right big toe and at the base of the other toes on that foot and Achilles tendinopathy in my right heel. Most of the time it's not too bad, but for the last few days all my affected joints are really sore. I know you can get flare ups with rheumatoid arthritis - is it similar with OA? And what's the best way of dealing with it ?