Why is my son banging his head? My 15 month old son keeps banging his head. He will go up to something and bang his head against it eg wall, cupboard, floor, this morning was a banging a toy, so it hurts and he cries. Lately it has been banging his head on the floor over and over. Keep asking him to stop as it is going to hurt him as he starts to get upset but keeps doing it. Is this just a phase?