My daughter also had torticollis she is an ex 28 Weeker, now 2.5.
I think it’s common for most babies, but being premie and possibly not being able to do tummy time or rotate head positions as much could make it more common for preemies. We doubled up tummy time and made sure he was sleeping on either side of his head. It ended up resolving on its own but generally they will wear a helmet for a few months and it’ll correct.
My baby has this (not preemie but did have a traumatic birth and this is a result of injury during birth). I’ve been doing the physio exercises with her for a week now and already can see an improvement. Hopefully you’ll have positive results too, sending healing vibes mama.