My LO always bumping his head.

It actually start when he was 7 mos, when he started to crawl. When he reach the wall he hit his head on the wall a couple of times. So i make him stop and carry him. I though it's normal but until now he's 1yr and 5mos, mostly when he is sleepy or upset in a matter he always bump his head on the wall. It's not actualy really hard but he always do it. Do i need to worry moms?