It is most commonly seen in vaginal
infection like Chlamydia, gonorrhea, vaginal
inflammation etc. it could also be due to disease of endometrium that is lining of uterus, polyps (mass) in uterus and cervix, fibroid tumors etc. You should consult an expert nearby for internal examinations.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided.