Why do I get in-grown hairs and bumps after I get a short hair cut?

It seems that after each hair cut, I get in-grown hairs and bumps after a week or so. My hair is cut very short on the sides and on the top. Could it be the shampoo I use?Why do I get in-grown hairs and bumps after I get a short hair cut?
who the hell cuts your hair i would go somewhere else to get a hair cut or change your cheap shampoo cheap skate.

ojon