Under normal circumstances, mucus is cleared easily whenever you swallow and the body’s defense systems eliminates harmful bacteria. Occasionally, something malfunctions, due to a cold, allergies, or a myriad of other issues. When too much mucus builds up and is not cleared away, it can develop into an irritating drip down the back of the throat. In addition to post-nasal drip causing this irritating sensation, it can lead to sore throats, persistent coughs, and ear infections. If not treated properly, these symptoms can get worse and eventually become debilitating.