Head hittings. The tests may l approach.

My son is 4years old.he is very active.he always move from one place to another place at home.always hit his head with any object at least daily one time. He cry some time and not cry in some times.he always hit his head. So lam very worried about his brain.now he is no other side effects but l am very much afraid about his future.ln future it may be any problems come from this hittings.so,I want to check up his brain.what are the tests may l approach. Is it any problems come with this hits or is it my fear only. Is it any tests compulsory or no need to worry.he has only problem is he not using words and sentences properly now yet.ls it came from this hits.lam very much warried about his speech. So l need your help to know i need any doctor consultation to this problem or is it my useless fear only.please give me the answer.my son is only 4 years old only