Abdominal Pain in a 15-Year-Old Adolescent Girl

A 15-year-old adolescent girl taking an oral contraceptive had 3 days of pain in a 1-cm area of the lower left abdominal quadrant. She had no nausea/vomiting, diarrhea, hematochezia, bloating, or anorexia; no precipitating factors for the pain; and no history of pregnancy, abdominal surgery, or abdominal trauma. Results from laboratory tests, endoscopy, and abdominal computed tomography were normal. What is the diagnosis and what would you do next?