I saw a GI doctor and he took a very lengthy and involved history. As a young child I recall having very painful stomach aches, being very constipated with rock hard stools and vomiting a lot. I lived in a very stressful household (alcoholic lived there) and it was like walking on egg shells. Seemed to manifest in my stomach. Now I have the opposite problem as I described above. Life now is extremely calm, low key and relaxed. I used to work in a job where a co-worker was harassing me (boss knew but nobody did anything) and it got to the point in the morning prior to work I would vomit or have terrible diarrhea because of the thought of having to work in that dysfunctional environment.
So my GI doc did both a colonoscopy then an upper/lower GI (EGD) and ruled out a bunch of stuff. The culture for H-Pylori was negative, despite him finding two tiny ulcers. He put me on Protonix which I took for a couple of years. I finally quit taking it. However because of the two ulcers he couldn't say for certain if the ulcers caused the problems or if it was IBS. My ulcers went away and I still had a lot of symptoms, so I believe it's IBS.