oh we were so worried when our DS started doing this! The first few nights we were up with him, stressing that he was in pain...then we realised HE was asleep, and we were the tired ones up worrying!
So we moved him into his own room - it passed in a couple of weeks.

You so sound like me though - at the time NO ONE seemed to understand how LOUD he was. It's no small grumble. It's freaky!

But...it DOES pass. good luck!