From what you're saying, it's not clear if a specific diagnosis is appropriate for your child or not. However, if you have concerns, absolutely have him assessed. Your pediatrician should be able to refer you to appropriate professionals in your area, and this is often the first step to receiving needed services. Regardless of diagnosis, you're having some difficulty, and there's no reason not to aggressively seek some help.
I have a 6 year old mild autistic son, when I found out he was autistic I did tons of studying and asked all kinds of doctors about it, your son doesn't have autism, my son was also diagnosed with ADHD. Your son sounds like he has a behavioral problem or ADHD, however doctors won't diagnose your son with ADHD till he is about 6 yrs old. Best luck to you, God Bless