Welcome to Healing Well, sorry to hear you are suffering. Please try not to worry, everyone (including me lol) has at some point thought they have a brain tumour because of the incessant pain, but usually pain is one of the last symptoms of such a tumour that often arrives after diagnosis because of other extreme symptoms!
My advice would be to get yourself to a Neurologist who is a Headache Specialist. A Headache Specialist knows so much more about Headache that a run of the mill Neurologist - who in fact knows fairly little about headache. A HS will find the best way forward for you with the right treatment and diagnosis.
Hope this helps, take care
Co-Moderator of the Migraine/Headache Forum
DX: Hemicrania Continua, Chronic Migraine, IBS, Allergic Rhinitis and Heart Murmur
Meds: Imigran Injections, High Flow Oxygen, Mebeverine, Lansoprazole, Nasonex and Clarityn