Hi. Thanks for your query and an elucidate history for a 10 year old girl.. The commonest cause of pain in abdomen of a girl child who is just 10 years old with a history of sore throat and headache is the tummy tonsils. Yummy tonsils means , the enlarged lymph nodes in the mesentery, the fatty suspensory curtain for the intestine. The develop as a result of infected throat material , reaching via the intestines to the draining lymph nodes. These can be well seen on high resolution ultrasonography and once diagnosed need a careful and continuous evaluation as to how the treatment is being helping for the resolution. Investigations:: of blood, urine and stool. Throat swab for gram staining and culture and sensitivity. USG guided FNAC of the lymph nodes if possible. Treatment in the form of a 3 week course of antibiotics and anti-inflammatory medicines may resolve the problem. Ultrasonography would help to confirm or rule out other problems like Appendicitis, diverticulitis and so on ...