A 22-years-old man presents with a history of a headache for 6 months which is mainly in the frontal region, occasionally associated with nausea. He has been taking paracetamol 3g per day, Hydroxycodeine 50 mg 3 times a day and Aspirin 300 mg 3 times a day for a headache but only with temporary relief from symptoms no focal signs on neurological examinations. What is the diagnosis?