I don't know what is wrong but after reading your detailed account of all the tests you've had my first reaction was you are too medically informed. Look at the simple possibilities. Heartburn? Emotional stress? Are you getting regular exercise? How is your diet? Getting proper nutrition? Have you thought about alternative health practioners? Meditation? seek other avenues than conventional medicine for help. Do your own research. Get in touch with your own intuition. Simplify. Get quiet. You sound a little obsessed. I truly wish you well.