Pinch/shock like feeling in one nostril that causes a temporary head pressure. what is this?

Likely benign: Some form of trigeminal irritation of a terminal nasal nerve branch which is hypersensitive for any number of reasons & activates the trigeminovascular system of the brainstem in the mildest of ways to produce what could be interpreted as a very subtle "knock on the door" of what under other scenarios could become a migraine headache. If you don't have headaches I'd just watch this for now.