My Husband Has Had Joint Pain. Hips, Back Now Shoulder.

My husband has had joint pain. Hips, back now shoulder. He is usually very strong and has alot of stamina. He is stressed and working alot, but unusually tired and these joints ache. This seemed to come on quickly. He had an xray and the shoulder is inflamed and the doctor said the bones look discolored. He is scheduled for full body scans. I can't stop thinking cancer. Is there something else I can think of?