My daughter had the same problem. She's 19 and just had her gall bladder removed yesterday. Her diagnostic tests all came back negative, too, but she kept having problem. The doctor kept insisting that it was her gallbladder, and ordered a hydascan (not sure of the spelling). This test showed billiary dyskenesia which means (I believe) that her gall bladder was functioning at a reduced capacity -- hers was 35%. In addition to the symptoms you indicate, she also had a greenish-yellow tint to the skin directly around her mouth. Since the surgery, that coloration has disappear. Although she has had pain from the actual surgery -- her other symptoms have disappeared.