Re: Weird sensation in upper back
I had the same tingly (like bug bite)sensations in my upper back, along the bra line. It turns out that I have a herniated thoracic disc (T 8-9). This is pretty rare, and my neurologist wasn't sure that my insurance would cover my MRI and had to be sneaky to get it approved. As far as I've been told, herniated thoarcic discs can affect anything from the herniation down, so I don't know if that would cause any symptoms in your arms (then again, I'm not a doctor). I've had the tingling off and on for a year and a half, have worn a brace, done PT, but nothing seems to be effetive. I don't know your level of pain; mine's more of an uncomfortable annoyance (though slowly progressing).
Initially, I waited two months to see my regular doctor and waited another two months to see the neurologist. Both were doubtful that anything was there. One the films came back, I was referred to a neurosurgeon who has made all referrals since that time. In any event, I'd rather live with it at this point than go through a thorocotomy.