I have had a really bad headache all day that has been off and on. I took some Excedrin (when I woke up this morning) which seemed to help. Now, it has gotten really bad with a shock that runs down my right leg and causes it to convulse. I tried to use heat on my forehead to relieve the pain, and now it is centered behind my right ear. Any ideas of what this is or how to get rid of it?