Back in 2019, I was travelling in a bus, and the bus hit the sudden breaks and my head hit the steel pole on the bus. It pained for a while. I didn't care it back then and went on with the rest of my day. Later, I also had slight pain in the same area(right side of forehead). Talked to a doctor over phone and he said that it's nothing to worry about and just apply warm compress over the area. Within 3-4 days, the pain went away too. 

But now here I am. Now my mind has convinced me that something bad has happened to my skull and brain during that incident. And I can't get over that worry. I was so carefree when this actually happened and months later I got reminded of this incident and now I'm worried whether something's wrong.