I have always had severe stomach pain. I am an avid runner (8- 10 miles every day, no matter the weather or my health condition). I have constant diarrhea. When I run in the morning I actually have to stop and hid behind a bush because the diarrhea comes straight out of me...and there is a lot of it. This happens at least 1-2 times over the course of running for an hour and 20 min. For the rest of the day it continues, but the stools get harder. I have constant gas pain. I burn a lot more than what I take in...I under eat. I thought I had collides; this has been going on for years but has gotten much worse within the past year. I was sitting at my desk this morning and bright yellow liquid came out of me (i had no control over it). What is going on?