Vulvar Vestibulitis: This condition is characterized by chronic pain and discomfort in the vulvar area, particularly during intercourse. The pain is often localized to one area and can be accompanied by itching. The fact that the symptoms are confined to the right side of the vaginal wall supports this diagnosis.

Vaginal Yeast Infection (Localized): Although the question mentions no unusual odor or discharge, a localized yeast infection could cause itching and pain, especially if it's confined to one area of the vaginal wall.
Vulvar Dermatitis: This condition involves inflammation of the vulvar skin and can cause itching, burning, and pain, especially during intercourse. It could be localized to one side, fitting the patient's symptoms.
Endometriosis (Localized): Endometriosis can cause painful intercourse (dyspareunia), and if the endometrial implants are localized to one side of the vaginal wall, it could explain the unilateral symptoms.

Vulvar Cancer: Although rare, vulvar cancer can present with localized pain, itching, and discomfort, especially during intercourse. It's crucial to rule out this diagnosis due to its severe implications.
Genital Herpes (Localized Outbreak): A localized herpes outbreak could cause pain and itching on one side of the vaginal wall. Given the potential for serious complications and the importance of antiviral treatment, this diagnosis should not be missed.

Vulvar Lichen Sclerosus: This is a rare condition that can cause itching, pain, and scarring on the vulva. It's less common but could explain the symptoms if other diagnoses are ruled out.
Vaginal Cyst or Abscess (Localized): A cyst or abscess on the right side of the vaginal wall could cause localized pain and itching during intercourse. These are less common causes but should be considered in the differential diagnosis.