what would cause for when im closing my eyes or trying to get to sleep thata sharp ring noise goes off in my ears and it wont stop making it impossible me to sleep. it happens every 10 seconds or so when my eyes are closed. it starts off quiet and gets louder and louder and starts getting into almost a screech. it sounds similar to somthing like nails on a chalkboard....what could cause this and how can i fix it?