Hello Welcome in H.C.M. I have gone through your query regarding reasons for sore throat. Sore throat is the infection of throat it may be viral or bacterial. Throat may get infection directly from external contact by eating infected items or inhaling in polluted atmosphere. but most of the time infection reaches to throat from other near by infections as from sinuses, tonsils, infected oral cavity and lastly from lungs. So all cases of sore throat should be examined along with above sites also for getting complete information about disease and similarly investigations should also involve all above to established proper diagnosis. Regards.