Welcome to HCM,
Your symptoms are suggesting me that you are having some allergic reaction
because of burnt food, which is causing all these symptoms.The symptoms are due to release of mediators of allergy
which is responsible for your symptoms.
The protrusion of the mass below the belly button should be examined physically to find out the reason.
I would suggest you to test yourself with different allergen by skin prick test, after identifying the allergen you could avoid the allergen or you can take immunotherapy either by subcutaneous immunotherapy or sublingual immunotherapy
I would advise you to consult your doctor for physical examination and find out the reason for the mass just below the belly.