REM Sleep Disorder and Tinnitus?

Okay, from what I understand, during sleep, the body's muscles are supposed to shut down so we don't act out dreams. When I was younger my parents told me I grinded my teeth at night. From what I understand grinding teeth at night can cause tinnitus.

Do I have this information correct or it some kind of other disorder that causes muscles to operate during sleep or do I have everything wrong and the muscles don't shut off at sleep?

If it isn't called REM sleep disorder what is the correct name?

Aside, from bruxism (grinding teeth) could REM sleep disorder cause tinnitus in some other way?