Dogs stick their paw in their mouth and rub their gums?

Fred has been doing this a lot lately, where he will take his paw and rub his mouth and gums alos, it's only on one side. Can this be tooth problem or stuck food??

I lifted his gum and looked at his teeth and everything looks totally fine. What was weird was he did it right when he woke up this morning too. I even looked at the paws and everything looks good. Maybe he has itchy gums or something?

Typical men

Mitzy used to do this odd head movement after eating sometimes....then I realized that she had food stuck on a tooth and was trying to get it off!  She has a tiny mouth with crooked teeth (result of a backyard breeder).