Your little boy is probably perfectly normal except for the fact that he doesn't understand what socially acceptable behavior is yet. That's part of what they learn at school.
No hitting, no pushing, no hugging...keep your hands to yourself.
No offense intended, but watching boxing probably isn't the best. Two guys stand in a ring and beat the heck out of each other and little kids don't understand there is pain involved. Even basketball, guys push and shove and fight for a ball and get knocked down sometimes. Football, same thing...it's all about tackling someone.
There is nothing wrong with sports and I have a son, but it's kind of like letting them watch some cartoons too young. I grew up watching Tom and Jerry and Roadrunner, but let's face it, someone always gets caught in a trap or an anvil falls on their heads or they're trying to blow each other up.
I'm not saying you've done anything wrong, please don't take it that way, but very little kids don't understand the difference between what they watch and how it applies to them in every day life.
Lots of kids do better with one on one attention but that doesn't necessarily mean anything at such a young age.
He doesn't sound antisocial. He doesn't sound agressive beyond perhaps acting out things that he's seen.
I would just come right out and ask the school what their point is in having him evaluated or what they feel their position is. No sense in beating around the bush about it. How many times do they want him evaluated? What is the outcome they are expecting from it?
If they feel your son have behavioral issues, they should just come out and say so.
He's been there 3 months. He's 3 years old.
I've taken care of lots of kids who were overly active or pushy and shovey, but I just dealt with it and let them know that was not allowed.
I was as firm with them as my own kids and their parents knew it and had no problem with it. That's how kids learn to get along and play nice.
If your son's school is basically telling you there is a problem without really saying it, they need to spit it out.
If this is your son's first attempt at social interaction, it seems that they would keep that in mind.
Or at least be bluntly honest.
I would request a meeting with them to go over all f this and look into other options for your son.
In the meantime, you also need to work with him at home about not hitting or pushing because it's NOT the same as playing.
Fun for him, but not fun for the kids that are getting hit or pushed.
That's NOT how we play.
He's young and he likely has no idea he's doing anything wrong so you have to help him with that. Some kid will hit him or push him back and he'll never see it coming if he thinks it's just playing.
I would be carefuly about letting him watch anything, yes, even sports, until he's old enough to understand that whole thing better.
This is the age where they truly begin to form their ideas about interaction and I would think the school would be more helpful to you about it as opposed to recommending evaluations. But, it depends on their tolerance levels too.
I wish you the best.