Oesophagus Reflux

I need to learn how and why this could happen (something to do with the lower esophageal sphincter, perhaps?)

Hope this helps
stomach acid reflux when the lower esophageal sphincter (LES) does not work correctly. This sphincter is usually tightly closed and only opens when food passes from the esophagus into the stomach. In addition to the conditions listed under "Who is he?" There are a number of factors that may cause the LES to open and allow stomach acid reflux. These include eating meals very important, lie within two to three hours to eat, and taking certain medications, including diazepam, meperidine, theophylline, morphine, prostaglandins, calcium channel blockers, nitrate heart medications, and anticholinergic drugs and adrenergic receptors. If you are prone to acid reflux, eating greasy foods and foods like chocolate and peppermint can also relax the LES. Caffeine, nicotine and alcohol can also aggravate acid reflux.

Firstly, please bear in mind that the lower esophageal sphincter is functional and does not exist as an anatomic entity. Normally, the LES is physiologically simply having a certain positive pressure applied by the muscle tone in the lower third of the esophagus. In contrast, at least in those of normal weight, there is a slight negative pressure in the abdominal cavity (approximately -4 cm water pressure). In some people, there is a loss of muscle tone in the lower esophagus, sometimes caused by drugs (even caffeine or a component of peppermint can do), or even a structural anomaly. Perhaps most often, there is a loss of negative pressure in the abdominal cavity, which can occur with an extra ten pounds of fat, for example. Or, since you lot esophagus with an initial o, I might suggest a stone extra weight?