What Causes Soreness And Itching In Throat On Intake Of Certain Foods?

i been having this problem on and off last few years this time is worse than ever.i thought i have allergic to red pepper because after every time i eat that first my throat get sore and itch after that lots of mucus coming up from throat but now a days seems like any food i eat same symptoms start except time i eat food with lot of fat.it really bothers me its up to the point i am scared of food to eat sometimes i wait until i get so hungry i couldn t stand it.i don t know for sure but this symptom started while i was drinking alkaline water.is it possible alkaline water destroyed my stomach balance ?