You may have a problem with your gallbladder. The pain you describe is pretty classic for gallstones, a poorly-functioning gallbladder or some other issue in the biliary tree. Time to head to the doctor! :-)
I agree with Jaybay. If your family has any history of liver or galbaladder problems, then you should deffinately be making an appointment. For a few days, track the pain. Record everything you eat, when you exercise, when you're sleeping, what position you were in when you feel the pain. Try to be specific about where the pain is an how it feels. This might seem a little tedious, but it will deffinately come in handy for your doctor. They will be able to tell if you have gas (which can manifest in this area), a food allergy, or something more serious. But deffinately make an appointment soon so you can get this all figured out and stop having the pain. I have pain in the exact same area, which happens to be a problem with my liver, but that's my case. I can tell you now, they will most likely draw blood, and possibly take an x-ray or ultrasound (this is what they did with me).