Heartburn is the most common symptom of GERD. This feels like burning chest pain that begins behind your breastbone and moves upward to your neck and throat. There can be a sour, acidic taste as stomach acid moves upward. It is typical for the heartburn to be worse when lying down or bending over. This chest pain can be mistaken for the pain associated with heart disease, but exercise is often tied to heart disease pain, while heartburn usually doesn’t result from exertion.