Chest pain in myocardiac infarction?

During an MI, you feel pain in your chest because there are pain receptors throughout your body. Pain is essentially your body telling the brain that something is wrong, and in the case of an MI that something wrong is a blockage of the coronary arteries and subsequent death of cardiac muscle. The reason why the pain sometimes spreads to the neck and arm is due to the fact that the pain receptors in the heart are sending such a large amount of information that the body becomes overwhelmed, causing the brain to loose track of where the pain actually is. And it's pretty much just pain receptors that send the signals.