Occasionally have a sharp pain that resides in vagina and continues up to uterus/left ovary. What could be causing this?

vaginal pain. Since the pain comes and goes it could be related to the menstrual cycle, such as an ovarian cyst (egg), or perhaps with bowel movements, the rectum is also in the pelvis and being constipated can be uncomfortable. Getting a pelvic ultrasound when you have the pain could help find an answer. If the pain is after intercourse then that problem could also be discussed with your provider with an exam.