I had the same pains for over a year and would eat Tums like crazy. I never knew what it was until I was rushed to the hospital because I couldn't stand up from the pain. I was very tender underneath the right-side of my ribs, and the pain was very bad in my back. The doctor ended up doing an ultrasound, and my gall bladder was removed a couple hours later. If you are having that much pain...it's not acid reflux. Next time you see your doctor request an ultrasound to see if you have any stones.