All of a sudden while sitting quietly,,my 15yo cat acted like her front paw had some type of issue

I'am laying down next to my cat,she looking at me,me her,. we were having one of those bonding moments when you kinda stare at each other.  All of a sudden she went to her front paw like something stung her, but nothing stung her. She licked it. 3 seconds later it was over.

any ideas or clues-why she did that?  at 15yo, i am always looking for clues to what may be taking place in her aging body. 

Ritz sometimes does that too; she is around five years old. Sometimes she 'flicks', like she has a charlie horse.
I wouldn't worry about it. Though of course if the behavior increases or she exhibits other not-normal-to-her symptoms, I'd call the vet.

Both if my cats do a a flick here and there of front leg. The older one more then the younger. Seems to be after alot of play however.