Tough to say without evaluation, however there are plenty of possibilities. This can include GERD, an ulcer, inflammation of the upper digestive tract, liver/gallbladder problems, or irritable bowel disease.
I would consider an upper GI series or upper endoscopy to evaluate the upper digestive system (looking for GERD or an ulcer). Blood tests for a bacteria known as H Pylori (associated with inflammation or an ulcer) can be considered.
If these tests are negative, you can then consider an abdominal ultrasound to look at the liver and gallbladder.
If there is an association with change in bowel habits, you can consider irritable bowel disease as a diagnosis and optimize treatment for this condition.
You can discuss these options with your personal physician or in conjunction with a GI evaluation.
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.
Medical Weblog:
kevinmd_b