Hey, Kids need not understand or express everything on their mind in the way we adults do. She could be getting stomach ache because she is tensed, scared or worried about something which she is not expressing directly. It should help to consult a psychologist. Consulting a psychologist or counseling would just mean understanding your child better and helping her express freely. Please feel free to go ahead and consult a psychologist nearby. I am sure your daughter will be better in no time. Take Care.