What Causes Sore Rash On Spine?

hello, i have a sore rash along my spine, mainly at the top of and spreading outwards but not further than in between my shoulder blades. i am very tired and run down as completing my phd, i've also been having family problems and have been in psychotherapy for the past six months. i have been overeating in the evenings. please could you advise me what the rash could be? it is very itchy bumps and almost blistering so its sore to touch and warm not hot too touch. thanks sarah tel: 0000