DEAR DOCTOR K: I've had a headache every day for at least six months. Painkillers don't help much. I know headaches are common, and I don't like calling my doctor unless it's a serious problem. Should I call him?
DEAR READER: Yes, you should. I imagine you're thinking that because headaches are common, they rarely indicate a serious underlying problem -- like a brain tumor. That's true. I also imagine that you have suffered from headaches for a long time, although you didn't say that. You may think that if you've had the problem a long time, it can't be serious.