Hi there, yes it could be the ears nose and throat is the place to go, I had it start when I was 22 after visiting a brand new golf course, I was allergic to the stuff used on the grass, had a severe allergic reaction but never took anything to relieve it as we were headed to the snow and everything was shut. A week later I could hear this hiss sound esepcially when it was quite, and wen i turn me head go all off balance, I went the dr got antibiotics, that didnt help the hiss, went to specialist who said my inner ear was permanently damaged. I am now 45 and the hiss is 10 times worse to the point I have lost hearing on my left side.Hope your diagnosis is better for you, if inner ear damaged from a recent allergy or sinus infection basically nothing can be done and each new allergy or infection makes it worse
Go see an ENT (Ear, Nose and Throat) Doctor. They specialize in this. It could be an inner ear infection, or sinsus, allergy.