S.T. is usually caused by nerves. The nerves cause a pulling of muscles in the neck area. Usually severe cases of S.T. are caused from injury and misaligments in the spinal columns resulting in the nervous system not to function normally. Your baby's problem is not because of nerves. It is the cause of either injury to the spinal column either at birth or it could've happend during these last few months either by a fall or an accidental jerking of the neck area.
Babies are very delicate.
I don't believe that surgery is the answer just yet. If the doctors don't know what is causing this, chances are that surgery can make matters worse. First just going to a regular MD is a waist of time. Your faith and prayers will heal your child if you surrender your life to Jesus Christ. Remember there is no cure for S.T. it only goes into remission to come back later on in life.