Headache and fever are common symptoms of several kinds of illnesses. Mild types like the seasonal flu virus and allergies can cause these symptoms. Sometimes getting a fever can give you a headache. write some more symptoms like cough, fever timing, fatigue.get some lab test CBC, urine culture.inmean time you can have hot water gargle with salt, drink some hot water, and take some paracetamol. in some cases, it may signal that your body is fighting a more serious infection or illness. f you feel sever than go to an emergency .