What Is The Cause And Treatment For Abdominal Pain And Fever?

my daughter (3 yo) is having abdominal pain and fever. we medicated her for fever with Motrin and Tylenol and she does have episodes without pain or fever throughout the day, not sure if it s because of medication. But as soon as she starts complaining of pain, sure enough she has a fever. This has been going on for over 3 days now. Also she has a poor appetite. I notice that her belly is more hot during these episodes and it feels overly active.