what ever you do dont put him on medicine for it.you could be doing more harm than good.And be glad that is all he has going on in his life.Because the side effects to the medicines they use for adhd and add have very bad side effects and you can end up dealing with more that what you are right now.And you cant revers some of them once they get them.
and your child is to young to worry about adhd right now.
Thats what 3 year olds do move riggle , jump, leap and play, its normal, I doubt if its ADHD make sure the child has plenty of outside activities, and is using up his energy, why does it bother you if he moves ?