Although I've had a heart scan and a halter monitor with all normal results, I continue to experience sharp chest pain that comes on suddenly from my shoulder which is extremely painful, I feel like my shoulders are pulling away, numbness down both arms, light headedness and short of breath. The episode happened again today while at work, I had my blood pressure tested and it was fine, I take BP medication. Today's episode lasted more then 1 minute (normally it's less then a minute). after the episode I feel tired and sleepy for most of the day and experience a sharp stabbing pain on my back. Could I have a heart problem that is difficult to detect?