1. Chest pain caused by angina due to coronary heart disease is located in the middle to lower third of the sternum, with unclear boundaries. It is often triggered by physical activities or emotional excitement and may radiate to the throat, lower jaw, left shoulder, and inner side of the left arm. The pain lasts for a few minutes to more than ten minutes, typically between three to five minutes, and rarely exceeds half an hour. It can be relieved by rest or by taking nitroglycerin under the tongue. The nature of the pain is feelings of stuffiness, pressure, or constriction, and may also feel like a burning sensation, but is not sharp like needle pricks or cuts.

2. The location and nature of the chest pain in acute myocardial infarction are the same as with angina, but it lasts longer, is more severe, and its triggers are less evident. It can occur even while at rest, accompanied by symptoms such as sweating, nausea, vomiting, heart palpitations, and difficulty breathing. Unlike with angina, regular rest or taking nitroglycerin under the tongue does not completely alleviate the pain.