Stomach pain on daily basis. We do next?

My daughter's stomach pain started a month ago. She initially felt better after taking Cyclopam syrup, but the pain returned. We took her to our PD, who provided treatment and advised an abdominal sonography. sonography report showed 3mm kidney stones on both sides. We then consulted a kidney specialist who prescribed treatment after which she felt better. However after a few days, the pain returned consistently located in the center above her belly button as it was from day one. We revisited the kidney specialist, but he ruled out kidney stones is not cause and advised us to consult a pediatrician. We then took her to a different pediatrician who provided treatment and suggested observation. Also he said chances of stomach ulcers less likely. He advised continuing treatment for a week and monitoring the situation. Currently she plays normally but during pain episodes, she cries intensely. These episodes occur daily basis. What should we do next? Please Help.