Postnasal drip is mucous that runs from the nose down the back of the throat, often causing a cough, according to the American Academy of Family Physicians. The purpose of mucous is to lubricate and clean nasal passages. Under normal circumstances, the mucous is swallowed without the individual realizing it.

Throat dryness can be annoying, particularly if dryness makes swallowing uncomfortable. Dryness in the back of the throat can occur due to allergies, illnesses or reduced moisture in the air.

A runny nose is usually just one symptom of an overall problem, such as a cold, allergies or exposure to any number of irritants. The blood vessels and nasal tissues in your nose produce excess mucus, which can either travel through your nostrils and out your nose or down the back of your throat as post-nasal drip.

It’s not uncommon to experience nasal stuffiness and congestion while exercising during pollen season -- but sometimes those symptoms may not be related to allergies or may occur while exercising indoors. If this happens, you may be suffering from a condition called exercise-induced rhinitis, or EIR.

Post nasal drip can cause discomfort, especially in the form of a sore throat and excess mucus. Treating the underlying cause of post nasal drip can reduce or even eliminate symptoms altogether, but in some cases--like a viral infection--you may have to manage symptoms until it passes.

Most people probably felt it at one time or another. A lump in the back of the throat that doesn't go away when they swallow or clear their throat and sometimes comes with a stuffy nose or an itchy throat. Post nasal drip is a common symptom of a cold or allergies that occurs when the nasal membranes become obstructed.