My grandaughter menstruates every two weeks since she was 10 years old now almost 11 what treatment is available she is in a lot of pain

See your doc: A lot of time girls at her age may have what's called anovulatory cycles, where one hormone is released in anticipation of an egg. Normally the egg is released, and the ovary produces another hormone that helps get the uterus prepared properly. When that doesn't happen, as is normal in early menarche, there can be erosion in the uterus and bleeding. There are other reasons too, and treatments.