baby rocking head back and forth

My one month old tends to shake his head in a back and forth motion kind of fast randomly, it may be something to do with him being tired cause it tends to be mostly when he’s sleepy. I’m wondering is this something I should be looking in to or if anyone else has experienced this? Just making sure it’s not going to be a problem in the long run and my baby will be perfectly healthy and smart.

I’m going to ask his doctor but it’s nice to hear other moms stories.