I Have A L7 Yr Old Daughter Who Has Been

i have a l7 yr old daughter who has been having major stomach pains. we have seen a pediatric gastr oenterologist at rainbow hospital in cleveland. last wk she had a colonoscopy and endoscopy done with little to no results. they said it just showed irritation in the esophagus and the stomach. last night and again an hour ago she started having the strong stomach pains. the pain is to where she rolls in the floor crying in pain. the dr. has her taking 2 prilosec aday. when the pain begins she has bentyl that she takes for the pain. also she burps up strong sulfur or rotten egg smells. is there anything else that you can recommend that i do or give her that is over the counter. Thank You