First time I've hit my head on anything in the past year
I was getting into bed of a night and as I went to lay my head down without thinking misjudged how far up I was sitting and connected with the back of my head on the metal horizontal pole that makes up the headrest of the bed. It was more than just a little tap as it definitely hurt for a minute.
Of course, straight away the headache returns, but i'm very aware of the increased focus you have on symptoms after any sort of slight hit.