I'm not sure how much this will help with the pain, but about not being able to pop when you want to: I found that if I try too often to pop certain joints, it doesn't pop whenever I try. I have to wait a while, a few hours, half a day, etc. until the fluid/oxygen builds up enough to be able to pop. Then its more of a release and there is less pain because I'm not aggrivating the joint throughout the day trying to get it to pop when it''s not ready.
P