I have pain in my upper abdomen, underneath my ribs just beneath the sternum?

You should have stated the pain you have to make sure that everything is covered. The pain you have in your abdomen area is caused by tight back muscles for when they are tight they can press into the nerves, as they leave the spine, going to the organs. Pressure on the nerves to the stomach causes it to release more gastric acid which will burn your stomach lining to give yo pains in the area you have indicated. Pressure on the nerves to your colon or anus wil cause them to tighten up so nothing can pass to plug you up. To get rid of the problems you have to free up your back muscles to release the pressure off the nerves, and then drink a large glass of water to get you going again, and here's how to free them up: Back: (do while sitting on a chair) Place your left hand on your left leg next to your body. Place your right hand over your left shoulder, fingers over the back and the palm in the front, and firmly pull down on them and hold. After 30 seconds slowly lower your body forward and to the outside of your left leg, keeping your left arm as straight as possible. When you reach your lap remain there for another 10 seconds, then release the pressure but rest there for another 30 seconds. Then reverse your hand positions and do your right side. For best results relax your body first by taking a deep breath and exhaling then remain this relaxed.

Alot of pain killers give people stomach aches because they don't eat prior to taking the pill. I have had the same problem and also constipation is common with pain killers. Just try eating before you take the meds and see if it goes away, which I hope it does. Tummy problems are the worst! I'd go to a doctor, which yes.. Gastroenterolgist is correct, if you don't feel better from eating, give it a day to work. Feel better!