Should I be worried?

Pa

For a week now, when he gets angry/frustrated, he hits his head. He will smack and bang his head repeatedly and sorta spaces out while doing it. Yesterday he worried me even more because when my nail client said hi to him, he ran to my husbands huge toolbox and banged his head repeatedly on it!!! Then, at bedtime he was so angry about having to go to sleep that he kept bitting and hitting himself. Is this a normal thing at this age??? Something else??? HELLLLPPP