Kind of a long shot but what I'm asking for here is anyone who has had a similar problem and what they've done to help, lessen, or stop this sound entirely. Tonight I'm going to go out and buy ear plugs and see if it helps at all. Doubtful seeing as the sound is being caused by my head but worth a shot.
So far I've also tried to sleep with a loud fan on but it didn't seem to help.
From what I've read the more you worry about it / let yourself get annoyed by it the worse it will get.
TL;dr - Loud high pitched noise, can't sleep. Suggestions?