For a while, I have noticed bumps on the back of my neck close to where my hairline starts. There are two bigger ones along with several smaller ones. They are pretty hard and they hurt only with pressure. There's no other pain and no other symptoms (coughing, fever, etc.). My grandfather on my dad's side died of skin cancer years ago and my other grandfather is suffering horribly from it. I told my mom and she simply said to keep an eye on it. Should I be worried?