Absolutely yes, get her seen by someone as soon as possible. The earlier you start, the easier and quicker it is to fix.

You don't need a referral for a chiropractor, osteopath or physio - you should just be able to book in. If she has a torticollis, that means she doesn't have freedom of movement and while she wouldn't be in pain, she certainly isn't as physically comfortable as she should be. 4 months old is not too late, my DS wasn't seeing his osteo till nearly 5 months of age.

I presume the physio your paed has recommended is a specialist in this field, and I don't see why you can't ring the paed's office and get the contact details for the physio and chase them up yourself.

Time to start jumping up and down and being a protective mummy bear, hun.