One year old daughter

Hi my daughter does strange things and I’m wondering if it’s a cause for concern.

She does these things where she hits her head randomly with her hand. We do the thing where we cover our mouths and take it off really quick while doing the “ahhhhhh” and she loves to say it and do it to herself (I really hope you know what I’m talking about” and then she’ll start hitting herself on her head, HARD. And then she’ll do these things randomly where she throws her head back multiple times hitting whatever it is behind her, whether it’s a pillow, her car seat, the wall, the couch, the floor, doesn’t matter. It sounds brutal and we always tell her to stop. But is that normal behavior? Should I be concerned?