hi thank you for the query I have gone through your query and would give you few possibilities of sudden throat pain upper respiratory infections pharyngitis laryngitis tonsillitis soreness of back of the tongue and viral or bacterial infections could be the cause of the sudden onset of throat pain as there are no constitutional symptoms like fever which you didn t mentioned I think in my opinion it could be due to reflux of acid into throat.. which irritates the mucosa and result in pain...see your GP and evaluate the pain completely and start medication as advised by your doctor hope I have answered your query thank you regards DR Alekhya