Final answer:
The pain in a myocardial infarction is caused by a lack of blood flow and oxygen to the heart muscle due to a blockage in the coronary arteries, leading to the death of heart muscle cells.
Step-by-step explanation:
The pain you are experiencing during a myocardial infarction, often referred to as a heart attack, is mainly due to the lack of blood flow and oxygen to the heart muscle (myocardium). This usually happens when one or more of your coronary arteries become blocked, typically by a blood clot or the rupture of an atherosclerotic plaque. The blockage leads to death of cardiac muscle cells because they are deprived of oxygen and nutrients, resulting in a heart attack. The severe chest pain, often described as pressure or squeezing in nature, can sometimes radiate to the jaw, neck, or left arm.