Hello,
This pain should go away after putting heat pads on abdomen and taking anti inflammatory drugs like Ibuprofen. If the symptoms persist then pelvic inflammatory disease should be ruled out.
Pelvic inflammatory disease is an infection of the uterus, fallopian tubes or ovaries. It occurs when bacteria move upward from a woman's vagina or cervix to her uterus or fallopian tubes. I sincerely advise you to consult a gynecologist and get cervical swabs and pelvic ultrasound done to find out whether PID is responsible for your symptoms.
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.
Btw it was the last day of my period so there wasn't much flow at all. I don't know if that makes a difference.