When I was getting checked out for my pain problems, I suspected my gall bladder, I was way out there, it was Gastric Reflux Disease, the Doctor told me the pain for gall bladder is on the right hand side, under the rib cage close to the center, you can also get polps in your gall bladder not just stones.

If you have suffered heartburn before you will have an inclination if it is similar or not, keep in mind severe heartburn can cause pain all around your upper back and shoulder,really I think you should get yourself to the Doctor smartly for a correct diagnosis,it will elimnate all your worry and it may be nothing much that can easily be treated.,hope you are feeling somewhat better today.,Keep us posted won't you? HUGS