What Causes Intermittent Itching In Vaginal Area?

TI last had sex last year in june, everything was quite normal until now , last month got a lipoma removed and was on antibiotics, this month just before my periods began I had had little bit momentary pain in myboth breasts which went away with periods, but soon after my periods got over I had unusual itching in my vagina,and I scratched it often ....though the intensity of itching has gone down,the itchiness comes and goes, there are no bumps or sores neither there is any pain bleeding or abnormal discharge ! I even tested negative for hiv , do I have other std ?