I would consider to get a sensory profile done by an Occupational Therapist

There is no harm in going to the doctor or pediatrician to get their opinion. My son, from an early age, would lash out and become angry as well as being very shy. I took him to a peditrician for their opinion as autism runs in our family. They were not concerned as all the issues I was having at home rarely were seen by his teachers at kindy. He is almost 7 and still has these tendancies at home but is fairly well behaved at school, definitely no violence. I would have a chat to his teachers and see what they say as well, most kids react differently at school then they do at home. Good Luck!

Children do develop fears. The dark and loud noises can be common. It’s always a sensitive issue with having no friends. Remember it’s quality not quantity in friends. What about try an outside of school activity like a martial art or athletics. Not necessarily team sports.

I’d see a Doctor for peace of mind and also it may make life easier for your son.