Hi, As per your complain it seems that sore throat can occur due to causes like bacterial or viral throat infection, post nasal drip, and acid reflux. Secondly black colour of tongue seems to be most probably due to a condition known as Black Hairy tongue that is a harmless condition. It can be due to a number of causes like overgrowth of bacteria or fungus, improper oral hygiene, food debris accumulation, taking medication containing Pepto Bismol. I would suggest you to maintain a good hygiene status like cleaning tongue with a tongue scraper, using a soft toothbrush to scrape your tongue. Gargle with 1:1 solution of hydrogen peroxide and water. Take raw foods like carrots etc as they clean the tongue by frictional action. It can take a few days to resolve and in case if it does not resolve consult a Dentist and get evaluated. Hope this information helps. Let me know if I can assist you further. Thanks and regards, Dr. Honey Nandwani Arora