I did have a under tummy bit as well but again it wasn't painful. I agree that it doesn't sound quite right and that you should push for an answer. Put aside your own perceptions. Doctors see things all the time that us 'normal' people would think are yuck or ugly. In my opinion - bodies just generally are kind of ugly!
ps. You may be 'clinically obese' but you aren't that big. Certainly shouldn't be embarrassed about showing your belly to your doctor. Good luck!