I've fortunately never had this happen to me after a flight, but I have heard that it does occasionally happen, though it's not widely known by the public. It has something to do with the change in air pressure and its effect on the fluid in the inner ear. This may be why some who are vulnerable to ear damage may be advised to use antihistamines while flying, because they tend to dry up the fluids in the head.

I'm surprised the doctor hadn't known about this, and the virus story seems a really ridiculous cover for their ignorance. Please, find another practitioner. Look for help at a medical facility doing medical research, in your area, perhaps at a university, where there will be more specialists. Or a place like the Mayo Clinic.

I hope you are successful in finding relief. So very sorry this is happening to you.