I would almost be certain it's from lesions.
I'll make this short and if any questions just ask....
If your having the pain under your left ribs, side, back and shoulder, strongly ask your doctor to examine you by laparoscopy. It's the ONLY way the reason for my pain would have ever been found.
I had my band placed Jan,11.2010 and prolapsed May, 2010 and removed July 20,2010. I started having severe left upper back pain and pain underneath left ribs before prolaps.The pain continued to get worse after prolaps especially when walking and on a full stomach. It was a stabbing pain through the left ribs and directly through the back and shoulder. I would also describe it as though I had been kicked in the left kidney type of sensation in my left side.
After having CTscan's,and an UGI along with second opinions, they were convinced it was coming from bulging disc in my back. I refused to accept that and in the meantime the pain continued to get worse but would get better if I laid down for awhile. The pain ended up getting worse just by sitting for a few hours, driving a few hours(sitting) or walking for a short time and was getting unbearable.
To make it short, I went to the Cleveland Clinic and was seen by bariatric surgeon Dr. Stacy Brethauer(HIGHLY RECOMMENDED)! He did and endoscopy the day before Thanksgiving to find my stomach was twisted. He then did surgery 2 days later to untwist stomach and look for any other problems. During laparoscopy to untwist the stomach he found that I had a dense lesion attached from my stomach to my liver tethering my liver and causing it to tear over time. The liver is why I had the severe pain which gave me the unusual sensation as though I had been kicked hard in the kidney on the left side. Also, the pain was worse on a full stomach due to the lesion pulling on my liver due to being attached to the stomach.
PS. The stomach twist was from the band placement but is supposed to be put back in proper anatomical position by the surgeon when removing the band.