Subluxation is a real medical term, it is an incomplete or partial dislocation (latin: luxatio) of a joint or an organ. As such if you have a subluxation, a dislocated joint or organ, you need to seek real medical attention.
Recently I hurt my neck — I don’t know exactly what I did, but whatever it was it hurts. I *think* I slept wrong on it and it has hurt for days. We have a sleep number bed and it slowly loses air over the course of a month or so, so if you don’t every once in a while bump it back up you end up sleeping on a really really soft (incorrect) bed. And since I’m no longer 12, any hurt I get seems to take a while to heal.