However, because this problem is all along your back and shoulders, I don't think it is shingles. I think you have severe acne
, which is hard to treat, but there is always help and hope.
I agree that you probably have celiac disease or are at least very sensitive to gluten.
Try a gluten free diet for a month to see if it helps. Allergies and food sensitivities CAN affect your skin.
As you know, the alcohol is not doing your stomach any good. It could have caused an ulcer.