Suggest Treatment For Fever And Stomachache In Children

My daughter is 5 years old, weighs about 45 pounds, and is constantly complaining about not feeling good. Specifically, she complains of her stomach hurting. She regularly has a fever (about every 3 to 5 weeks) and it is associated with the stomach ache and sometimes she will throw up. Sometimes she ll have other symptoms like swollen tonsils although she does not complain of a sore throat. A few times she says that her ear bothers her too. The strep tests always come back negative. Urine tests always come back ok too as well as xrays. She had a bout of this about a month ago that lasted 10 days (there were a few days in there that she acted normally for part of the day). During that time she hardly ate and slept all the time. Then 2 weeks ago she had a brief episode that lasted 2 days. I took her to the hospital for that one since she was crying because of the pain. When I say episode or bout I mean that a fever is associated with the other symptoms. When she is not in the middle of an episode she acts and plays normally but will occasionally through the day say I don t feel good or my stomach hurts . Do you have any suggestions?