I am a 45 year old woman who has had migraines since I was about 20. I have gotten some relief from Imitrex. I have now got one treatment of Botox Nov 24/07, which seems to help a lot. Only 2 days of headaches in 2 months. About 6 weeks ago I started getting a very painfull pounding at the top of my head whenever I stand or sit quickly. Or when I laugh, sneeze, cough or stain to do anything at all. It only lasts about 5 - 10 beats, but it is VERY painful and scary. I almost pass out with the pain. I am on blood pressure meds and have a perfect blood pressure now. I also have been taking Effexor for anixity for about 2 years and it is really helping. I just went for a CT scan and it did not show any problems. I am not on some very strong painkillers for the pounding headaches and it helps a bit but at times it feel like my head will explode. Does any one have any ideas what could be wrong with me??? Thanks