What Causes Pain Radiating From Neck To Shoulders And Lower Back?

Back pain that started approx. 4 weeks ago with fever and neck pain. Also infection in bladder. Have had 2 antibiotics and the pain has radiated from my neck, shoulders down to the lower back. At first the pain was so bad that I could hardly move. It is some better now, but I do not feel well enough to do much. This came on suddenly. I have been very active up to this point.