Stomach pains and discomfort are driving me mad.

Stomach pains and discomfort are driving me mad. It started about seven years ago when I got a really bad pain in my stomach during PE in high school. I had to sit down it was that bad. Since then I have been plagued with stomach problems. It's on the upper right of my abdomen and is a dull, aching "griping" pain. It makes me hot and can make me feel sick. Recently I have started a pain on my lower left, although not that often. Several times I've also had discomfort across my entire stomach which then progresses to pain whenever I move. Two years ago that kind of pain came on and I could barely walk. I had half a mind to flag down a passing ambulance. It hasn't got that bad since, but I still have the upper right pain which drives me mad. The doctors have said its pulled muscle, growing pain and IBS. I've had blood tests, ultrasounds, the works. They reckon everything is OK. I've had random dizziness, acid reflux and a sometimes over-the-top gag reflex when trying to eat. Also I have lost weight - since I'm already skinny enough to be the Jolly Roger's stunt double that's a bad thing.