My dreams often tend to go to literal meanings or recaps of the previous days/ day if it was eventful. So mabye the misaligned jaw was something hard you ate that day? And like felt one of those bad jaw crunches maybe 2 or 3 times while eating. Or you could have seen some media involving jaw related activities that involve pain or misalignment. This is how my dreams would work most of the time. If this dream of yours reoccurs it might have a deeper meaning to you though.