I am with K9soul regarding doctors. I think everything that happens in your bowels is very close to your whole personality: it is scientifically proven that thinking and feeling is not only a brain thing but also a stomach and bowel thing.

(Whenever I'm stressed I have problems myself- this is why I read about it- although it cannot compare to what you are going through).

So there may be a long way in front of you as the doctor doesn't find a reason for your pain- but I send you all my best wishes to help you on that way.