A sore throat, also known as pharyngitis, can be caused for a variety of reasons. In some cases it is simply the result of overuse of your voice. A sore throat often develops when your mouth becomes very dry, or from sleeping with your mouth open. However, it can also result from a viral infection in your nose and throat, such as a common cold. Strep throat, also known as streptococcal pharyngitis, is a more serious bacterial infection that causes a sore and scratchy throat. The pain in the throat often comes on quickly and can make swallowing difficult and painful. Symptoms of strep throat also include tender lymph nodes, and tonsils that become swollen and/or red with white patches or streaks of pus. Tonsillitis is inflammation of tissue located at the back of your throat. Indications of tonsillitis include sore throat, pain and difficulty swallowing, and swollen lymph nodes in the neck. Allergies can create Postnasal drip, secretions from the nose that drain down into your throat, and cause your throat to become sore. Upper respiratory infections are viral infections that affect your nose, throat, and airways. This infection can also contribute to a sore throat due to postnasal drip. Exposure to smoke and pollution can leave your throat feeling dry, scratchy, irritated, and sore.