Consider the following scenario: A mother wakes up with a headache. She didn't have one when she went to bed, but she does now. In fact, she's woken up with a headache more often than not for the past month. She has coped with it by taking pain relievers. Many days, that has been enough, but she has noticed other pains as well. When she's gone to lunch with her coworkers or her friends, sometimes ...