This is similar to my situation. I started with pain in my right shoulder, radiating down my biceps, especially where the tendons attached to my shoulder and elbow. Hurt so bad that I couldn't raise my arm over my head. I iced it, heated it, took ibuprofen and never got much relief. Always the worst in the morning. Physicians suspected a torn rotator cuff even though I coundnt remember doing anything to cause an injury. X-rays and MRI showed some inflammation of tendons and bursa.
I began physical therapy which really didn't help much either. Then my left shoulder began to hurt, not quite as badly, but in the same places. Then my groin where the thigh muscle tendons attached and the back of my knees, too.
My dr ran blood test to eliminate Lupus and RA. He concluded PMR and put me on prednisone and almost immediately all my symptoms disappeared.
Don't know what your pain is due to, but it seems quite similar to my experience
