advice

i am 23 years old and i have a problem about my vagina i feel itching and there is yellow come out from my vagina almost 1 year i feel this kind of infection i am using BETADINE WASH i buy from medical store and almost 1 year i am using but only 2 or 3 days desapear then it will come again so please i want to know what kind of infection it is. and please give me advice what i have to do to desapear it is?