What Causes Swelling On Labia Majora?

sometimes something white almost looking like a light green color come out i feel when its coming down and it itches sometimes then my labia majora get swolen and it get dificult for me to walk the thing it that i dont be having sex a lot at first thought that it was an infection or because of having sex but its still happend even if i dont have sex?? its normal or do i need to see my doctor?