I had a tendency to lean on my elbows a lot whilst studying, and flex them whilst sleeping. Since then, though, I have put padding on my desk to support my elbows, and have been sleeping with an elbow brace to limit the degree of flexion. I would say that I do have poor posture, yes.

Recently, I have been having upper back pain associated with poorly cracking my spine in a twisting motion. This results in making it hard to breathe. I get sharp pain from between my shoulders, across my thorax, and into my lungs. This prevents me from being able to breathe normally (only shallow breaths permitted).

Do you think that this could be related to TOS?

Sorry to hear about your situation! It sounds remarkably frustrating. Did you ever find out what the cause to your initial symptoms was, seeing as it was not ulnar nerve compression?

Thank you for putting this into another perspective for me! I guess it is better to still be looking for a cause of a problem, than to get surgery that is futile.