I relate but I also have Autism haha

I also have autism, but I was recently diagnosed with EDS, a connective tissue disorder that sounds like it could be related. Do you have sore joints and feel like you're hypermobile?

I would do some research on excessive daytime sleepiness and narcolepsy. You can experience cataplexy with both I think and that sounds like what you might be describing happening to your jaw. I’m not an expert and don’t experience it personally but it sounds like you might be experiencing a mild form of cataplexy.