If you haven't been to a cardiologist, or at least had an EKG, that would be a prudent measure.
From my scoliosis, I get upper and mid left back pain. When I have my chin down towards my chest, I get a pain that radiates from my back, around the side, and into my chest -- feeling deep, where my heart is. I've been t a cardio lately, and know what's going on with my heart. One of my doctors said that it is likely due to one of my damaged nerve roots in the upper thoracic.
Perhaps, something similar is happening with you. It will be hard to diagnose for certain, however. But an MRI may be appropriate if the pain is severe and ongoing.
A physiotherapist might also have ideas, especially if it is due to a joint displacement, muscular or skeletal issues. Perhaps take a shot at that, given your doctor's advice. See the physio at least a time or two and find out what comes of it.
Anyhow, welcome to the chronic pain board.
C4-T4 Scoliosis (disk degeneration, stenosis, narrowed neuroforamen, bone spurs), RT hip and SI joint damage from car accident. Also, pectus excavatum, supraventricular tacycardia and mitral valve prolapse syndrome.
Current meds:20mg Oxycontin daily, Oxycodone 5-10mg for BT. .25-.5mg xanax as needed for sleep, Verapamil 240mg SR (for tachycardia).