It seems to me that your son just might have some self esteem issues. He hits himself and other people because he does not no of anyway to show his frustration. I am assuming that he sees himself as a faliure when he cannot complete a certain task. Just try to do things that will make him feel good about himself. Try encouraging him and not being too competitive. On the other hand don't spoil him. That will be even worse and he will use the problem to his advantage. I had this sort of thing hapen in my family. Here is a website that will help you more than I could.

http://www.childdevelopmentinfo.com/...f_esteem.shtml

And please don't feel that it is your fault because it is not. I am sure you are a good mom and will do whatever you must for your son.

Good luck.
Roman James