I've began having this recently, usually while trying to get a lucid dream. It does feel weird, makes it hard to fall asleep.
Strangely enough, when I sleep, I forget about the entire thing, even if it is twitching, I wouldn't notice.
Also, I've been noticing that I've been able to stay up for 3 days straight (Holy stuff I have a huge temper at this point) but now I actually get tired and fall asleep before my brother does, which is usually before me. He's also older than me.
This all started after my eye twitch thing.