I can't help much - but just wanted to say I really, really feel for you. You're far too young to be having all these awful health issues.
I have the beginnings of arthritis in my knuckles - but then I'm 55. The cold
definately makes it worse. Exercise is good - try to keep everything as supple as you can.
My mum suffers with it very badly - her neck practically locks up. She was advised to use a heat pad - she sits there with one on each evening like she's wearing a scarf, it really helps her. Good luck
Sally x