Lisa, some of the symptoms sound like you may be having a problem with your gallbladder. Have you asked your doc if he's considered that? Testing for that condition would include a gallbladder ultrasound and HIDA scan with CCK injection along with a blood test that checks your liver and pancreatic enzyme levels.
You may want to consider following a low fat diet to see if that helps. For some with gallbladder issues it does help.
What specific tests did they do in the ER?