Shoulder-neck muscles birth defect?

Dear Ask The Doctor: Born with head on shoulder muscle did not develope correctly had to do exercises the first 6 months of my life. Now my jaw bone on the left side is sunk in the right side is normal does this have a specific name to describe this

Dear Kelly: Unfortunately your explanation is very vague, but it might be a peripheral nervous system (brachial plexus) injury at birth or lack of development of certain muscles in your shoulder. It is unclear if the jaw bone problem, after so many years, might be or not associated with the birth issue. Either case, I recommend to have an evaluation by an orthopedic surgeon of your shoulder and your jaw and decide from there the future treatment option.