There are so many things that can cause
symptoms like yours including gallbladder, sphincter of oddi dysfunction,
pancreatitis, etc.
Doing your own research can only help. Check out the "First Principles of Gastroenterology", http://gastroresource.com/GITextbook/en/Default.htm. I would take special note of the biliary system, Sphincter of Oddi Dysfunction and pancreatitis.
Here are some links for you:
http://www.merck.com/mmhe/sec10/ch140/ch140b.html
http://www.romecriteria.