At times when you feel pain in the internal organs such as your heart and lungs, you better not take any chances and see a doctor right away. These parts of the respiratory and cardiac system of your body are quite delicate and taking it for granted can cause dire consequences.
You can always say you have a high tolerance for pain. However, when your key organs are in question, do not play Mr. Know-it-all. Visit a doctor since it can lead to something more serious than you think. Get necessary tests and have them evaluated so that you can pinpoint the actual cause of it all.