You're starting to notice that it's not only obvious things -- like too much spicy food or coffee -- that trigger painful heartburn symptoms. Now you're getting heartburn in the middle of the afternoon, just working at your desk, or sitting on the sofa at home. Sometimes you wake up at night with pain in the back of your throat and that awful taste of yesterday's dinner. You groan: not again. Sit up in bed and wonder: Is this more serious than simple heartburn?