Welcome to JustAnswer Health...and thank you for your question. I am a verified Expert and am delighted to help you today. One thing that can cause alot of problems are tonsil stones.. does he still have his tonsils?
Yes, he does.
Tonsil stones, also known as tonsiliths are balls of putrid saliva and food remnants that can accumulate in the tonsil folds causing irritation, pain, ear problems and generalized ill feeling. Here is a video to see what these are... please be warned it is Gross... but I think it's an important consideration in his case..and something a Doctor can easily overlook:
Ok, you're right that was gross. How do we find out if that is what this is?
His Dentist or Doctor needs to look using a q-tip to move the folds. IT is difficult for most people to be able to do this themselves because of the gag reflex. If tonsil stones are found they can be very easily and painless removed by the Doctor.
What are the chances that this might be early mouth or throat cancer?
At 21, honestly... slim to none.
he COULD have an allergy to cigarettes or marijuana which could cause the symptoms he is having.