The real purpose of the heart

From early age I was thought that human's heart shape is equal to long circle. The heart is a muscle who makes 8000 litres of blood everyday. Heart has got two sides, in those two sides it makes some moves in every 4/5 second that blood could go in the right places. The heart is a muscle, so it's impossible to feel the pain in it. But I have never really believed it. They all were wrong. Terribly wrong. And everytime I feel the pain in my heart I am sure that I was learnt wrong. You know that feeling when you want to breath very deeply? You start to breathe deeper and deeper and suddenly you feel pain in your heart and you have to stop doing it... Or when you just feel so sad that it looks that someone is pulling into your heart the knife. Or when you expect from someone something and they just betray you... You feel dissapointed, your heart is just bleeding. In those moments I am sure that I was thought wrong. In those moments I think about every pain in my heart, which I felt during all my life and I also think of those who felt more pain than me. I think of those who had a heart attack. I can't even imagine what kind of pain they have felt... First their left arm start to get colder and colder, later it starts to melt inside; then head starts to ache with the pain that can not be described in any of the word, but if someone would write those words to explain the pain... It probably would burn this paper sheet. After that they finally feel the heart ache... The most terrible, most frustrating, exhausting, making them shout or scream and at the end of all those pains they finally feel how they are out of the oxygen, how they can not breath, nor shout, nor scream... In those moments when I think of it, I understand that I was wrong all my life...