Hi,
I'm a pediatric PT who works a lot with torticollis. Torticollis in babies has 2 main causes...he can be born with it from the way he was positioned in the uterus, or he can develop it after birth due to the way he is positioned every day. Many babies who have stomach problems, especially reflux, end up developing torticollis because their stomachs hurt, causing them to arch backward a lot and to turn their heads to the side, particularly if they refuse to lie on their stomachs. I also try to warn a lot of parents I meet if I see their babies slumped in a carseat or swing, because if they always slump to the same side it can cause torticollis. The muscle that gets too tight is the sternocleidomastoid (SCM) muscle which turns the face to one side and tilts the head to the opposite side. It can cause the baby's skull and face to grow a little bit asymmetrical (crooked) and can make it hard to a baby to sit straight, use both hands together, or learn to crawl. This can lead to scoliosis (worst case if not treated). In most babies it is mild and can be easily treated with physical therapy, however I highly suggest a physical therapist who sees mainly pediatrics because they will usually know many more tricks to help you. A therpist who just stretches the heck out of the baby's neck will often cause more stress than help. You should get a good home program with positioning suggestions and fun "exercises" you can play with your son. At this age it's so important for him to have lots of happy tummy time. Sometimes a helmet will be worn to help re-position the skull bones if the head is becoming mis-shaped, but it doesn't sound like your son has one, so that's a good sign. I'm really not sure, but it sounds like the orthopedist really has nothing more to offer and probably just wants a neurologist to make sure there is nothing else wrong that needs to be treated too. The GI doctor should help control the stomach problems so that the torticollis can get better. I hope this helps. There should be lots of info. available on the web, but some of it may be scary.