It's probably just a communication frustration issue as he is most likely just struggling to "communicate" as difficulty doing so can be very frustrating, however... it can escalate. I would not give him attention for his inappropriate behaviors and instead, try to help him find an appropriate "communication" method whatever it may be. His teachers/therapists should be able to help you.
I also wanted to say that any "self-injurious" behaviors such as biting himself should be completely ignored by all in every and all environments. My daughter used to bite her hand out of frustration and hit herself in the head out of frustration when she was 3 to 7 yrs old. Completely ignoring those self-abusive behaviors worked like magic. They faded to near extinction. We continue ignoring anything self-injurious to this day and she is 20 yrs now (but those behaviors are extremely rare anymore if at all). I hope your son's issues are simply something he'll get over in time, but I wouldn't assume that and I also would not give him any attention when he is having them, then super praise him verbally with smiles any time he displays appropriate communication in any way shape or form

Best wishes to you!!!
Just so you know- and you may already be aware- your son is entitled to a behavior modification plan to be put into place should such behaviors escalate and become a disruption in his education at school. He is entitled to have a behavioral analysis/plan in his IEP. I assume he is already in school. I just wanted to share that in case you haven't been informed, it's just a bit of info to keep in mind for the future
