My granddaughte, who is now 9, was diagnosed with ADHD this past school year. She is high energy but the problem was that she couldn't stay focused in class, would forget to finish assignments, and couldn't stay in her seat. She did fine in preschool, kindergarten, and first grade. Her teacher in second grade discussed the above mentioned difficulties with her mother who took her to the doctor who said she could be ADHD. My duaghter wanted to address it with diet but couldn't follow thru. Duh! She was a full time working single mother with 2 children. Her youngest, a boy, is special needs.
He wasn't talking by age 2. The pediatrician recommended that the school district evaluate him. As Judy said, they are required to provide evaluation and treatment if they find a disorder that is likely to interfere with learning in school.
I highly recommend that you have your son evaluatied thru the school district. Their offices are in the County Intermediate Education Service Disctrict. They are still providing speech and occupational therapy for him. He also is assigned a social worker who helped my daughter learn different ways of parenting him as well as telling her what her son neeced so that he wouldn't be so hyperactive and unmanagible. He does not have ADHD; at least that has been the diagnosis so far. He was in a special needs kindergarten even tho he's smart. He will remain with that same group for first grade while also being mainstreamed.
The school district is also helping my ADHD granddaughter by writing up an Individual Education Plan (IEP) which includes methods of teaching that work well with her. My daughter also felt strongly not to medicate her daughter. But she gave it a try. My granddaughter is focusing better, staying in her seat and completeing work much better with the medication.
I certainly would not medicate a 4 year old. There are other ways to treat ADHD or any other difficulty he might have.
His behavior sounds similar to your son's with the exception that he has difficulty forming words. One of his diagnosis is sensory procussing disorder. For my grandson, he needs heavy touch in order to feel. He's calmed down quite a bit but his hugs sometimes are so hard that I nearly lose my balance. He runs at me and into me without slowing down.
There is no charge for the school's evaluation and you still have the choice to follow their recommendations or not; to use their services or not.
I'm adding a note because of your self-description. Cud you be ADD/ADHD? My daughter is ADD. She was easily bored and always doing something. She had difficulty sleeping at night which then caused her to be cranky in the daytime. She also didn't want to take medication but eventually had to because she was having enough difficulty focusing that she was having difficulty at work. She also was impatient with her all of us. Why couldn't we think and move as fast as she could? She started medication which has made a very noticeable difference in her ability to do well at work and have more patience with everyone. She still has energy but is calmer.