Difficult to say without evaluation.
The workup that you had has been comprehensive, and would rule out many of the major causes.
More specialized tests can be done to evaluate the upper digestive tract. This can include a gastric emptying scan, 24-hr pH study and esophageal motility studies.
Another consideration would be Sphincter of Oddi dysfunction. This is a relatively rare disease that can lead to some of the symptoms. If suspected, a Sphincter of Oddi manometry can be done in conjunction with an ERCP.
These options can be discussed with your personal physician.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Kevin, M.D.
www.kevinmd.com