Sounds like your doctors need to expand their medical knowledge, because Post nasal drip can most definitely cause a sensation of nausea, not originated from the stomach.. I get the same thing and it drives me nuts some times.. It's like a "Nasal Nausea" I call it..--ha, ha Not sure what is the cause of mine, (hormonal, dairy?) as of yet.. And that lump feeling in my throat just really get's annoying.. Almost trigers a a false hunger feeling, in the midst of nausea, Very weird, but Real.. It's not in your head. Other folks do have the simliar sensation from Post Nasal drip. Might be good to try and figure out the cause of the increase mucus.