I dont know whether this helps but I have had the most horrenous headaches over the last few weeks! Yes weeks, and its turned out to be muscles in my neck causing them. I t wa so bad at one point, i went to A&E and was admitted to hospital and was given a CT Scan and lumbar puncture, thank god they were both clear. But at times the pain was unbearable. Just cant believe it was all to do with tense muscles, Bad posture and years of pent up stress. Just a thought for you. Pain killers didnt help my head either. Hope you get some relief from it soon xx