My daughter of 4 years have extreme abdominal cramps. The dr said it's gas trapped in her intestines. How do I relief the pain?

You can try Mylicon. which is also called simethicone which is for gas. However, if there are other symptoms, such as diarrhea, vomiting, fever, sore throat, or cough, I would recommend having her checked by her doctor again, to be sure it is not something else or something more serious.