What Causes Chest Pain?

I went to the ER yesterday with chest pain. they took EKG, blood & chest x-ray. they said I probably did have a mild heart attack. they said i could go home, a calculated risk and come back if i have more chest pain. OR i could be admitted to get the enzime and stress test. I opted to go home. i'm at work now but still have some pain. what should i do.