Head shaking a lot at night

During my 3AM pumpings I notice my baby is always having unsettled sleep where he moves a ton. He shakes his head side to side, which looks fairly violent and rough on the neck. I know to some extent this movement is typically to rock/lull them themselves to sleep, but it does make me wonder if he’s putting too much strain on the neck due to the jerkiness. He sleeps in a Zipadee sack thing right now and did the same in a swaddle. Neck is fairly strong at this point but he does seem to have slight torticollis and definitely favors one side, though he has range of motion on other side. Anyone have similar behaviors with their baby? Showing a video of this to doctor later this week...