C.H.
My son and daughter tilted their head to the left a bit too, but we brought them to a chiropractor and within a couple sessions, they were holding their head straight up and hasn't had any problems since then. It might be a quicker fix to seek out a chiropractor than physical therapy (just my opinion). My sisiter's baby tilts his head too and she is looking into seeing a chiropractor as well.
I know when we first inquired, the chirpractor said it's very common and that the younger the kid, the easier for them correct. I think my son took 2-3 appointments and that was it.
Good luck.