Since August 2014 I Have Had A Pain Start At

Since August 2014 I have had a pain start at the lower base left side of my head. It travels down the left side of my neck and when it hits my left shoulder,my left side of my neck,shoulder,left part of my face and sometimes my upper left side of my chest start tingling and sometimes I feel some numbness. I have gone to my heart doctor and after all possible tests done,he stated that it is not my heart. Never happened before in my life,what do you think it might be?