What Causes Pain In Right Side Of Ribs?

Hi, for the past couple of weeks I have had pain off and on below my right side of my ribs. I am exttemely nauseous. especially after I eat. Half the time i just don't feel like eating. I get tired real easy and i have headaches that seem to be right in my eyes. I have had really bad heartburn -indegestion no matter what i eat. i have been on oxycotin for 2 years now for a herniated disc in my back. I notice that when the meds are wearing off is when i feel extremely extremely sick. what do you think this could be