Had a headach for 4 days now ?

Causes of Headache: It depends on the character of it. Headache that is affecting one side of the body and it come all the time might indicate Migraine Headache with fever might mean infection After trauma might be something wrong with the brain Many causes of the headache and it might be very difficult to summarise in with no much additional information. I suggest to see your doctor for assessment and management.

Could be anything: Headaches could be due to simple viral infections or major brain tumours. It is difficult to say without more information and examination. It could be a tension headache, a viral infection, migraines, due to poor eyesight, meningitis or a haemorrhage. In short you need to see a Dr who will take a history and perform an examination, if needed you will be referred for a CT scan as well.

Evaluation: Would highly recommend an evaluation ideally by a Neurologist