Your dog might have been living with un-gentle children before he was with you. I would make sure that you give a lot of attention to your dog. Also, he may have anxiety over something. Take hi mto the vet...check hiom out. But remember,who is more important...your son or your dog? If your dog doesn't calm down soon, I would say it may be better for you ( and for your dog too, he may just not like little kids!)to find him another homw, not to upset you, though.