What could this pain in my side be?

Tuesday evening I was sick with a stomach virus. I was vomiting and had diarrhea. I slept through the night and felt better the next morning although I still had diarrhea. Over that Wednesday and Thursday I felt better but Friday the vomiting and diarrhea came back full force. I again handled it and come Saturday felt better. Sunday though it all came back and I decided to go to the ER. They drew blood and took X-Rays. They admitted me with an ileus (a type of bowel obstruction caused by dehydration). I spent the night at the hospital with constant fluids being given to me through an IV. The next morning the diarrhea started to dissipate and the vomiting was gone. I was discharged and told to rest and take it easy for a few days. Now today I feel better. The diarrhea is gone but I'm a bit constipated. No vomiting. I have a sharp pain in my right side at the ascending colon that comes and goes. It seems to feel better if I change positions. I'm guessing it's due to my week filled with abdominal stress but I'm also worried about the possibility of colon cancer or something. Woudn't they have been able to see a tumor or blockage with the X-Ray. I have no blood either in my stool. In the hospital I was given red jello which a few hours later my stool was orange looking. The doctor didn't think it was anything to worry about and all my stools since then have been normal in color. Wow personal. Anyways since leaving the hospital I've been staying hydrated and I'm wondering if maybe I'm upsetting my colon by not eating enough. In the past day I've had a few crackers and a very small meal. I've drank 2 sprites, an apple juice, 3 powerades, and some tea as well as three bags of the IV fluid pumped into me. My only symptom is the slight pain in my side so I'm not thinking colon cancer. Could I just be depriving myself of the foods I need. Any advice would be nice. Just wondering if anybody else has had this problem and if anybody knows if a tumor would've been noticeable on an X-Ray in the colon.