Hello,
For this pain any adhesions inside the pelvis should be ruled out. Missing of periods can be due to secondary amenorrhea. Secondary amenorrhea is when a woman who has had normal menstrual cycles stops getting her monthly period for 3 or more months.
Causes of secondary amenorrhea include stress and anxiety, malnutrition, depression, overexercising, sudden weight loss or gain (obesity),thyroid disorders and hormonal imbalance due to polycystic ovarian syndrome(PCOS).Smoking is also associated with secondary amenorrhea. Sometimes tumors of the ovaries and brain may also cause absence of menstruation.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.