Eating large meals before bedtime can also cause heartburn. Obesity, frequent bending over, lifting, and wearing very tight clothes can produce pressure on the stomach, which in turn causes heartburn. Smoking and certain medications can also trigger heartburn as well as stress as this is known to increase acid production and slows down the emptying of the stomach. You will experience a burning sensation that will begin in the upper abdomen and builds up behind the breastbone and makes your chest feels like burning. The burning sensation and the pain may even travel from your diaphragm to your throat, which may be accompanied by a bitter and sour taste. It can even feel like as if food is reentering your mouth. The biochemical method of diagnosing means that a probe will be placed via the nose and in to the esophagus. This will record the level of acidity in the lower of esophagus. This method is called Esophageal pH Monitoring, which can be sued to document acid reflux in real time. In the mechanical method, the doctor will try a method called Manometry. Examples of foods are chocolate, peppermint, alcohol, coffee, sugary foods, and fried and fatty foods. Smoking also weakens or relaxes the LES as well as certain medications. Pressure on stomach and eating large meals shortly before bedtime can also cause heartburn. Stress will also cause heartburn as this increases acid production and slow down the emptying of the stomach. One of the main causes of heartburn is the weakening of the sphincter. Basically, the sphincter acts as a valve that prevents stomach acid from reaching the esophagus. When it is relaxed or is weakened, stomach acid can get through the sphincter and eventually irritate it and cause heartburn. So, just what causes the sphincter to weaken or relax? Instead, use a wedge under the mattress or place a 6 inch block under the head of the bed. If you are overweight, you should start losing weight. And, you also have to stop smoking if you do smoke as nicotine can damage your LES or lower esophageal sphincter. Taking antacids can also work. This works by neutralizing the acid in your stomach and it should be taken 1 hour after meals or when you feel heartburn symptoms starting.