Have you asked for a referral to a gastroenterologist? If you truly feel that you have a physical issue that needs to be dx'd...then I would suggest this as a next step.
I would also start to use some coping skills to treat it from an anxiety standpoint as well...since this could end up being the cause, or at least a contributing factor.
Here is a link to our Resources that has great stress relieving exercises (links included) that you can get started on right away. Practicing these everyday can make a huge difference in how you feel.:)
https://www.healingwell.com/community/default.aspx?f=9&m=104206
Keep posting!
S.C.