Head banging

So every once in a while my daughter will walk up to a a wall and rest/ hit her head on the wall, but the last two night she walks up to the wall and repeatedly hit her head on the wall, very hard. It got to the point I have to keep her in the pack and play cause she will run straight to the wall and slam her head into the wall. I've given Motrin and Tylenol already and saw no change. Should I be worried? What can I do? She's not crying or anything that seem like she's in pain