When I look down, within a few seconds my back starts to tingle between my left shoulder blade and spine. Stops soon after looking up. Nerves?

Don'tStickYerNeckOut. Please check-out Dr. Jacques Jean Lhermitte's photo on Wikipedia. He's the guy that described something like you have. Yes, it has something to do with your nerves and if it persists for more than a week, or starts getting worse, you should see your doctor, or a neurologist to see if it has any indication of a serious nerve problem or is just a neck muscle strain or something else minor like that.