What Causes Spinal Pain With Nagging Muscle Ache?

This morning I had kind of a nagging muscle ache in my mid back to the right of my spine. Throughout the day it has grown to acute severe and covers what feels like a large area. It hurts to breathe and move, sharp, almost blinding, pain. I have had SI pain on the left side, but this is nothing like that kind of pain. I am 35, 5'8 and 250 lbs. I also have not done anything I know of to cause any kind of muscle strain. Tramadol has no effect on the pain.