BY MELISSA HOWELL Staff Writer mhowell@oklahoma.comIs it the flu or a cold? It's a question that perplexes many who suffer the occasional runny nose, fever, body ache and chills. The bottom line is you know you have the flu when you have intense fatigue, fever and aches, said Robert Welliver, M.D., chief of Pediatric Infectious Diseases at Children Hospital at University of Oklahoma Health Sciences Center. “Flu comes on much more quickly.Read more on NewsOK.com