What is wrong with my cat?

You can call your vet. It maybe seasonal allergies or dust mites/fleas or any other allergen . Example is food allergens or a vinyl floor or vinyl food dish. If it's a purebred breed then ask a vet. I have the same problems with endless airborne & food allergies plus topical allergies in my pure bred kitten and no vet can figure it out. Just trial & error. If you think it's ear mites.......it may be actually dust mites or another parasite that only a vet can determine with blood tests.