I used to get a lot of sore throats in college. I strongly believe that sugar caused a lot of the sore throats. Sugar suppresses your immune system which causes the throat to become inflamed. If you are drinking soda with sugar, try diet drinks instead. Soda has a lot of sugar in it. It may be very difficult to give up sugar completely so try not to eat/drink more than 50 grams a day. One can of soda has about that much in it, so it would be best if you drank no sugared sodas. Good luck!