I saw a weight loss doctor, and she said it was a b12 injection that was administered in my stomach. since then i have experienced spasms.

Shot: The B12 is probably not the problem, but the shot itself might have caused some irritation in your abdominal wall muscle. I would anticipate this to resolve, but if not get checked.

That's strange: I do not know of any reason to administer B12 via an injection into your abdomen. I would recommend seeing your regular physician to determine what may be causing your spasms, and whether or not you even need B12 injections.