Hi.. your daughter may be having simple gastritis and mild hepatomegaly may have no clinical significance and normal or not related to any disease. Recent viral infection can also give rise to mild hepatomegaly. When considering more severe causes may be due to leukaemia or other haematological malignancies..But these are associated with other clinical symptoms as impaired growth, easily getting caught to infections and bleeding menifestations and liver enlargement is moderate to severe. She needs more investigations like full blood count, blood picture, full liver profile and uss abdomen and also upper GI endoscopy when considered her stomachache. Best thing is to meet your family doctor or a consultant physician for further evaluations. Regards!