Not much I can offer really just empathy as I'm almost in the same situation as you although my should does go back in. I waiting to see a new Orthopod consultant whom my GP has referred me (after changing the referral to this guy as "he's more of a thinking Dr") I haven't a clue what "a thinking Dr" is other than one that doesn't want to try any further sugery with out really looking at the long term and treating me as a whole rather than just looking at my shoulders.
I will let you know how I get on when I see him.
Sorry I can't give you any solutions, I really wish i could
My best advice for now is to get a comfy polysling and support the arm, it should help a little with the tingling and coldness.