Hi. Thanks for your query and an elucidate history. No problem with a patient from Argentina. The commonest cause of pain in the lower left abdomen are : -Sigmoid colitis. Pelvic Inflammatory Disease. Salpingitis on the left side I would suggest the following: 5-day course of an antibiotic, metronidazole, probiotic, anti-spasmodic and Supportive treatment. Since the X-ray and the ultrasound are normal, nothing much to worry about. Further investigations of CT scan and enterolysis and colonoscopy and others needs to be done if there is no relief with medical line of management.