hiting himself

i dont know whats gotten into LO (2.5yr) lately. every time he gets in trouble he starts screaming "im not in trouble" and punches himself in the head. this all started in the past few days but i dont know how to get him to stop. the only way hell stop screaming is if you say his not in trouble anymore. anyone else LO do something like this? how do you get them to stop?

My son is 19 months and has been hitting himself in the head since he was about 10 months old any time he's told no or gets something taken away from him. It's his way of throwing a fit and his doctor said it's normal and just to ignore it because he's not going to do any real damage. Sometimes he slams his head into the wall and it sounds like he's gotta be hurting something and he even did it at his last doctor appointment when I blocked him from getting into a cabinet. I just ignore him and he gets over it. He's quite a bit younger than your LO, though....