I'm a 26 year old female and consider myself to be healthy. However in the last 10 days or so I've been getting sharp shooting pains that begin in my left shoulder and spread very quickly up towards my jaw and slightly down the top of my arm. The pain is extreme but over within seconds. It has occurred several times within the last week and a half. I've felt this pain once before about 2 years ago and when it happened that time it left me light headed. This has not happened this time round however. Any Ideas?