I have severe left shoulder and mid back pain, plus bloating...gallbladder?

That would be a very uncommon presentation for gall bladder disease but without a thorough history and physical it would be hard to tell. You may wish to start there. Gall bladder disease is typically diagnosed with history, physical, ultrasound, and scans

I agree with Dr. M's response. If your experiencing midback pain which radiates toward the shoulder, you may be dealing with an impingement of a nerve root from a spur or bulging intervertebral disc in the thoracic spine. In this case a neurologist could evaluate you. Appropriate testing would be done.