Smart of you to have the doctor check you for all the stuff it could be.
It might just be sweat, carrying smells from the food you eat. Our bodies are designed from the days when the human species was pre-verbal to put out smells at the crotch and underarms so people could communicate to each other that they had found good sources of food, things about their health, etc. The sweat glands concentrate the oils and salts from what we eat and deposit them in the crevices where there is hair and they would be not readily washed off. It's not useful or suitable nowadays, but it's a leftover evolutionary relic.
You might try wiping (the outside of the lips ONLY!!!) with some of the old-fashioned formula of Listerine ("original formula" -- the stinky kind) to see if the eucalyptus oil and menthol and other stuff they put in that formula will stop the natural oils and salts in your sweat from smelling so strong.