My 7-month old baby shakes his head from side to side when he's tired. he also flaps his arms a lot all the time. is this normal?

Usually normal: Head banging and arm flapping is a common way for children to soothe themselves and usually nothing to worry about. However, in some kids it can be part of a developmental problem. Frequent head banging or arm flapping, particularly if you're worried about a developmental delay or unusual social interactions, should be evaluated by a doctor.

Head shaking: He may be shaking his head because he is teething. Flapping his arms may be his way of enjoying himself