Mucus is normally swallowed unconsciously, but when there is a feeling of the mucus gathering in the throat or dripping from the back of your nose, it is called post-nasal drip.
When acid refluxes from the stomach into the esophagus, it is known as gastroesophageal reflux disease (GERD). If stomach acid travels up the esophagus into the throat, it is known as laryngopharyngeal reflux (LPR).