All the things you mentioned were tested except I have had my gall bladder removed. I am overweight, I do exercise on treadmill. I do carry most of my weight in the gut. thanks
First of all, what do you mean by "all the test run"? What types of tests?
If there really isn't a sign of anything wrong with your liver, gallbladder, pancreas, etc., then it might indeed be your posture. Might be a dumb question, but have you tried seeing a chiropractor? Also, do you exercise? If so, how much? And if you're overweight, where do you carry most of it? Might you be overcompensating in one area positionally because the area responsible for counterbalancing is weakened?
Good luck.