As an anaesthetist I examine the temporomandibular joint of every patient. A clicking jaw is v common. a jaw that pops out and in is less common but not that unusual.
The reason is that this joint is very lax - basically 2 separate bones held together by a floppy capsule.
If it isnt causing you problems, leave well alone. Surgery on this joint is not straightforward and has less than ideal results. It should be reserved for patients with specific problems, most commonly pain, where conservative management has failed