You say you can't take ibuprofen, but you took Advil, which is ibuprofen. You could be making things worse. Also, I don't remember you mentioning back pain before. Why not see your primary doctor about the back pain? It may not be related directly to your surgery. My back pain was related to my UC, not my surgery. If you go to the ER they do not deal with chronic issues, but just patch things up and send you home.