Hello dear, Thanks for being on healthcaremagic.com.I feel concerned for you.Headache can be primary like-Migraine or Stress headache or secondary to some structural brain disease. If your girlfriend would have presented to me as an outpatient,I would have asked her a few questions to answer your query well- 1)Headache is persistent or episodic? 2)If episodic,what is the frequency of episodes? 3)Is it accompanied with nausea or visual abnormalities? 4)Is it unilateral(on one side) or bilateral(on both sides)? 5)Does it increase on exposure to bright light or sound? 6)Is it accompanied with pain in neck? 7)Any history of seizures or loss of consciousness? Since she is having fever,she may need a brain imaging like computerised tomographic(CT) scan for evaluation. Please ask a follow up question with the relevant details,so that I can answer your query well.I hope it helps.