You may suggest/ask your doctor about a breath hydrogen test. If it is fructose malabsorption going on a strict Low FODMAP diet will help. I am not a doctor but have been threw a lot with my daughter for stomach pain.
Best of luck.
Hello,
The possible causes of this stomach ache are viral infections of the stomach, food intolerance like lactose. GERD (Gastro Esophageal Reflux Disease), where the acid contents of the stomach come up into the esophagus, Irritable Bowel Syndrome (IBS), malabsorption, inflammatory bowel diseases and various infections of the colon. Blood tests will help detect infections, besides stool examination which will reveal fat malabsorption. It is best to consult a primary care physician and discuss your concerns. Take a light diet and avoid fried fatty foods. Drink plenty of water and liquids. If the symptoms are severe or persistent visit a gastroenterologist. Treatment will depend on the underlying cause. Hope it helped.
Best luck and regards!