Could you please describe in detail some common signs of a heart attack that only appear when a real attack is taking place? Just so i dont end up waiting until its too late to call 911. Also will i be able to use a phone? Im paranoid because my family has history of bad heart. i often get sharp chest pain but it will be on and off for about 30 mins or so then disappear. And it will happen while im sitting down not straining myself. I am a 30yr old male, 130lbs.