I have had my band for going on 5 years, the EXTREME left shoulder pain is caused from a nerve that is located near the banding site, but the pain oddly enough radiates in you r left shoulder...it is normally caused by gas or eating in volume...for the best solution, lay on your left side and pass gas...believe me it WILL work.
The pain that you are feeling if caused by a nerve that is actually located near the banding location but radiates in the left shoulder area... I am going on my 5th year living with the band. Lay on your left side and let the gas pass. You will have instant relief...I've been there SEVERAL times.
I have been banded for almost five years now, the best way to get rid of the pain in to lay on your left side and let it rip. There is something about laying on the left that works miracles! This also works if you have the terrible pains that show up in your left shoulder---lay on your left!