Hi, Thanks for the query. I understand your oncern You seem to have vaginal infection (trichomoniasis or with secondary bacterial infection)... which causesitching ,burning & sore vaginal lips when subjected to friction while having sex. Vaginal infection &the stress caused.. leads to hormonal imbalance & delay in period. You need to get physical check up by a gynecologist followed by specific medication (fluconazole oral &vaginal pessaries ) in suitable dosage. (Depending on age.. body weight &severity of infection). Both sex partners need to be treated . Strict genital hygiene...abstinence till cure are the needs till cured.... by both sex partners Thanks