What Causes Persistent Fever Along With Burning In Eyes And Headaches?

My daughter constantly over the past year runs a fever of 99.0 and 100.4 at least 4 days a week. I have noticed nothing that triggers this such as environmental, activity, or diet. The symptoms that may be present are lethargy, burning eyes and a head ache....a basic blood panel was said to be normal by her Dr but something isnt right! Where do I start?