15 month old Hitting/Banging of head and self

So I am getting concerned that there may be something wrong with my sweet baby boy! He has been hitting his head or hitting himself when he gets frustrated or upset. this I understand because he doesn't know how to communicate. What is bothering me is that he is getting worse with it and he has started to do this randomly even when he is happy which is often... does anyone else's babies doing this... we have an appointment Friday. any one with experience please share!