@Minib: we altered his head position early on so he doesn't get flat head. You can do the same. Then, our life with him was a blur when we were overwhelmed by his colicness and moving. When he started being able to move his head left and right by himself, that's the problem that we noticed at about 6w. DH only agreed with me about this problem at around 10w.
We put him on the other side of the cot etc without any success. He always moves it back to the right. I am now putting his head to the left overnight after a feed. I move it back whenever he turns back to the right. I don't bother for nap because it is so hard to get him to nap and don't want to wake him up.