He's not mad or upset. He does this when I pick him up and sit him in my lap. He just throws his head back and goes stiff. I am trying to bend him back normally and he's so strong. He will relax and do it again. I'll pick him up and he will do it again. Should I be worried? He had an EEG done and brainwave activity was normal. He's 19 months. I need some advice, I don't know what else to do and can't find anything online about it. All it relates to is tantrums and he's not upset when he does this.