Head banging

No I am not talking about a rock concert, I am talking about Bears new thing. Well it is not really new, he did this for awhile a few months ago and then stopped. Back then it was the car seat and the couch and me. But now he is doing it again. He sits down in front of something, usually hard, and throws his head back repeatedly until I move him away. 5 minutes later he is back at it. I tried to ignore it, I would say "wow Bear, that must really hurt!" and walk away. But now he is doing it on the heater vent, corners of the wall, the TV, the fridge, and he tries it on other people heads too... I am just afraid he is going to cause brain damage. I even got down one night after he was in bed and tried it myself just to see what the thrill was, and believe you me, it hurts! Is this a phase? Is he autistic? I am not making light of the autism thing, I really am worried. The doc said not to worry, he seems fine. It doesn't seem so fine, when I watch my baby bang his head on the metal heater vent with this little weird smile on his face staring up into space. Not so fine. Really. I hope this is a phase. I can just see myself taking him to college and having to pad the walls in his dorm room...