Vaginal Yeast Infection (Candidiasis): Although the swab shows no infection, a normal Pap smear and the presence of white vaginal discharge with pain during sex are highly suggestive of a yeast infection, which may not always be detected by a routine swab. Symptoms can persist or recur if not properly treated.

Vaginismus: A condition characterized by involuntary muscle spasms in the vaginal wall, causing pain during sexual intercourse. The normal Pap smear and absence of infection on the swab support this diagnosis.
Vulvar Vestibulitis: Inflammation of the vulvar vestibule, which can cause pain during sex (dyspareunia) and may not be detected by routine swabs or Pap smears.
Endometriosis: Although not directly related to vaginal discharge, endometriosis can cause pain during sex due to the growth of endometrial tissue outside the uterus. The normal Pap smear does not rule out this condition.

Cervical or Endometrial Cancer: Although the Pap smear is normal, it is crucial not to miss the possibility of cancer, especially if symptoms persist. Further investigation, such as a colposcopy or endometrial biopsy, might be necessary if risk factors are present or if symptoms do not resolve.
Pelvic Inflammatory Disease (PID): PID can cause pain during sex and may not always present with abnormal Pap smear results or positive swabs. It's a critical diagnosis to consider due to potential long-term consequences on fertility.

Lichen Sclerosus: A rare skin condition that can cause white, patchy skin in the genital area and may lead to pain during sex. It requires a biopsy for diagnosis.
Desquamative Inflammatory Vaginitis (DIV): A rare condition characterized by a heavy, yellowish discharge and pain, which might not be detected by routine swabs. It requires specific diagnostic criteria for identification.