I was told that it was all in my head. The brain misses hearing high frequencies and it recreates them. Sometimes I have total silence right when I wake up, then as soon as my brain boots up, the noise starts up.
It’s sort of like the syndrome for the vision impaired. The brain knows the eyes are supposed to be seeing something. When it doesn’t, it creates hallucinations. I believe it is called Bonet syndrome. A lot of seniors are diagnosed with dementia when they really have this syndrome. My 100 year old mom has it.
Everything is in your head, Unless you are in a simulation of course