Suggest Treatment For Pain On Left Side Of Head And Arm

Hi I have been experiencing pain on the left side of my head since the 29th Dec 2014 despite being on gabapentin for the last 2 weeks 900mg a day I am still experiencing pain and constant pins and needles down my left arm which is occasionally having spasm which last up to 30 secs I am still doing daily routines but the pain wakes me in the night but I have been told that it isn't life threatening but I am getting worse not better with the medication ?