Burped after ate, then felt something twitch or pulsate not sure which sensation, under my chin, around upper pt if throat near mid left side. Idea?

Muscle twitch. I will bet it was a reflex spasm of your left sternocleidomastoid muscle. I would not worry.
Reconfiguration . Like a transformer your neck returned to default but there was a jamup/reset of one part. Never a problem unless continues. .