Thanks for the replies.

I've looked him over & palpated him numerous times & can't find ONE thing wrong. He doesn't seem to be in any pain, eats his hard kibble & treats like a piggy, doesn't get the runs or vomit.

It's not a constant thing, it happens about once every 15-30 minutes, maybe a few times in a row, thats why I thought it was a loose tooth that was getting in the way but none are loose.
I think he's still getting/just got done with getting in some puppy teeth in the back.

I guess I'll just keep a good eye on it, I'll get it checked out in a couple weeks when he goes back to the vets for his last vaccines. Unless of course it gets much worse before.