What is going on with my stomach?

Hi there, I'm a teen girl, and the Friday right before memorial day I woke up at 5 AM with this excruciating pain in the middle of my stomach, and I was crying too, which I never do from pain, I'm a tough cookie. Well I had volvulus repair when I was a week old because my intestines were twisted. I had an x-ray done, and it showed constipation so my doctor told me to eat fruits and ones with skin on them, no meat and pasta, I only lasted a week, Did that, wasn't getting any better.Now after I eat I get very nauseous and have to go to the bathroom. What is going on? It often feels like someone is tugging from the inside of my scar.