Stomach Pain after eating, getting worse!!?

For the past 6 months, I have been experiencing a severe pain between my rib cage after eating, the pain is below my bone and stops about 3 inches above my navel. I thought that I had pinpointed the cause to mushroom intolerance and entirely took these out of my diet. This weekend though, I have experienced the pain twice, and have been eating foods that I normally eat without problems. I am only 21 years old, is this irritable bowel syndrome or any ideas what is going on? The pain lasts about 4 hours, and nothing I have tried makes it stop.