I Have Painful Sore On My Throat, Tongue, & Cheek

I have painful sore on my throat, tongue, & cheek inside that is so painful and has been there since september 2014. it only changes position but never disappeared. i hav taken riboflavin, vitamin c, antibiotics(augmentin, ciproflacin, tavanic 500 etc at different times but no solution. Have done HIV Test(-ve), recurrent typhoid and malaria(yes almost every month); more than a year now... Takes lots of water(Yes as prescribed). Dont know what to do. Confused..