This is a painful condition making it very difficult to swallow, eat, speak and even breathe. It is brought on by colds and ‘flu (influenza) virusesĀ but bacterial infections or environmental factors may also give rise to inflammation of the mucous membranes lining the throat (pharynx) and the tonsils. Most sore throats are acute and heal without complications within 7 days. By contrast, chronic sore throats are of much longer duration.