Have you been to your doctor. That could be a sign of a heart attack or maybe indigestion. Please see your doctor as soon as possible.
It sounds like your gallbladder to me as well. Go an see and doctor as soon as possible, as it is a fairly easy problem to sort out and will stop the pain.
honestly I had some problems with right under my rib cage, if I would make a c with my hand and put it half on the front and half on my back that is where I felt the pain. What that was was my gall bladder going bad, they had to remove it. good luck