i've been having really similar problems myself recently. i've found that when i was out of work (ie, not typing everyday) my playing improved but now i'm working i get cramps and stuff. i'm trying chinese medicine as well as going to see a doctor cos this really isnt good. i think i might do what mark tremonti recommends and take a month off guitar (completely and utterly) and build my speed up again from scratch. atleast all the theory is already there.

i'll keep you posted on how this goes, but you've gotta give me a couple of weeks :)