I Have This Upper Back Pain, From My Left Shoulder

I have this upper back pain, from my left shoulder blade, left rotator cuff, to the level of my spine, sometimes I feel a pressure at the middle of the spine, that I need to lean forward curve to release the pressure in the middle. On and off spasm in the thoracic muscles. My GP could not determine what causes all of this. I'm still waiting for my physio appointment until now, and I wanted to be treated, how to take away this pain?