For The Last Past Four Or Five Days I Have

For the last past four or five days i have been have strong awful pain on my back upper left shoulder blades. The pain shoots down to my left elbow. It also feels like if pain was hitting my heart. The pain occurs everytime non stop is continuos. I cant sit, sleep, move or walk without feeling this sharp pain. It doesnt stop. What can i do? Im afraid of a heart attack. 28 years old by the way.