Hi C.,
You are very observant to have had this diagnosed so quickly. And you're smart to get your son into physical therapy quickly. This is going to be a long response, so I hope you don't mind, but here's what we went through and what I learned from dealing with my son's torticollis...
My son was diagnosed with torticollis at around 3 months of age. We started physical therapy right away, went weekly, and when he was around 5 months old, we added in visits to the chiropractor. The first visit to the chiro seemed to backfire, but subsequent visits really helped. The chiropractor's daughter also had torticollis, so she is very understanding of the frustrating nature of torticollis. By this I mean that my son would seem to be doing great, holding his neck straight and then he'd suddenly have a severe downturn and look kinked again for a week or more. As my pt and chiro told me, torticollis is a roller coaster, and as moms, we just have to keep doing our exercises and be patient. We have to learn to roll with it.
We continued pt until my son was about a year old, went for an additional check up once he learned to walk, which was when our pt said he was looking good enough to not have to continue treatments. My son is now 17 months, and occasionally he still gets tilted (like after a cold or teething), but for the most part, he holds his head straight. People who are around him a lot notice when he gets tilted again, but most people don't even see it. We still see the chiro every six weeks, and she helps remind me to keep up with the stretching, continue making exercises like a game (important once they're in their independent phase), etc. So the good news is that torticollis is very treatable, and with the physical therapy and chiro adjustments (if you choose to do chiro), kids with torticollis seem to "grow" out of it for the most part.
My son also was diagnosed with acid reflux at one month old. We put him on zantac and after a few months, his symptoms seemed to disapate. We also slept him on a wedge, which helped too. There is a condition called sandifer's syndrome in which kids with gerd show symptoms of torticollis, but upon treating the gerd, the torticollis also goes away. While I believe my son truly has torticollis (based on his movements in utero, difficult birth, chiropractor's observations, etc), we did see a strong connection between treating his acid reflux and his neck. At one point, we tried to take him off the zantac, and his neck completely reverted to it's "kinked" state. When we put him back on the zantac, his neck straightened. So I called his pediatrician and upped his zantac dose, at which point his neck straightend even more. You might look into acid reflux as a cause for your son's torticollis if you suspect anything with gerd...
Here's a bit what I learned, or wish I'd done differently: I wish I'd worked at the pt exercises harder when my son was an infant and more malleable. From reading the other responses, it seems that some infants don't mind the stretches as much, and there are varying degrees of tightness in the neck. Hopefully your son is more easy going than mine and has a relatively mild form! My little guy hated having his neck touched and was collicky on top of it, and sometimes it was hard for me to be really consistent with his stretches since he'd just scream. I didn't want to force him to stretch at that point because it seemed he'd tighten up his neck more when he got upset. From my point of view now, it seems like when he was little, I should have tried more variations of the stretches--using the boppy, carrying him like a football, working on getting my husband to make him look left if I was holding him upright, using the Bumbo once he could sit up to get him to look left, etc. My advice now is to try not to get too discouraged and use all the resources you've got to keep him looking the direction you want him to look.
I think my biggest breakthrough came at about 6 months when I learned that he loved watching Baby Einstein movies, and I'd let him watch them while holding him so that he had to look to the left to see the screen. This worked really well for us, since he was happy and I could stretch his neck without him minding much. Also, our chiro said that Baby Einstein was the only way her daughter would put up with tummy time for her torticollis treatments. So, even though I'm a big advocate of limiting screen time, I have to say that Baby Einstein really helped straighten my son's neck! :) I still use screen time now when my son has a tilted week--I just stick him in his high chair, turn it so that he has to look left, and put on Baby Signing or Elmo. He loves to watch them, and willingly looks left to see the TV. He's active enough now that I can't hold him and stretch him while we watch together.
We tried infant massage when my son was 10 months, and it completely backfired. I'm not sure why, but I imagine it was like when I've had a massage that's too deep and I get sore--at least that's what I imagine. My son had had a good two weeks, and the morning after we visited the infant massage, his neck was kinked again. Obviously, I didn't continue the massage after this. But I think massage could be a very beneficial treatment for some babies. Or maybe we needed a different massage therapist? It might be worth a shot for you...
My naturopath recommends craniosacral massage for torticollis, but we haven't tried this yet, mainly because the chiro said it didn't work for her daughter. It's another treatment that I've read on torticollis support sites that some people claim really helps. You might try that as well.
And finally--tummy time, tummy time, tummy time. Do whatever you can to encourage your baby to enjoy tummy time. And limit his time in containers like car seats, swings, infant seats. Anywhere where his neck and spine can just be relaxed into their curved position and not have to work at holding up his head.
Please feel free to contact me if you need support or want to discuss this further. I tried to type in everything that I remember helping. Good luck and god bless!