I have a spot on the back of my head that has hurt for the past 2 months. It's in the hairline but there isn't a ingrown hair or pimple. It's the kind of hurt like if your hair is dirty and you where a hat all day how it make your ends of your hair hurt. Hard to explain but it won't go away. It stops hurting if I take ibuprofen but comes back if I stop taking it. What is it