I believe I strained my shoulder muscle from a fall. I do have full movement; however, the deltoid muscle and possibly the bicep was strained. Knowing an MRI is the only machine to find out what really is going on, I wanted to look into some other options. Symptoms: Almost feels like nerve pain when I lay on my back. The pain builds gradually. Twisting the muscle back creates an intense burning sensation that can be relieved by coming back to the neutral position and rubbing on the upper arm/shoulder. The trapezius muscle seems to be affected a bit too.