Angina is chest pain or discomfort caused when the heart muscle doesn't get enough oxygen-rich blood. It may feel like pressure or squeezing in the chest. The discomfort also can occur in the shoulders, arms, neck, jaw, or back. Angina pain may even feel like indigestion. But, angina is not a disease. It is a symptom of an underlying heart problem and is usually a symptom of coronary heart disease (CHD).There are many  types of angina, including acute coronary syndrome, angina pectoris, chest pain, coronary artery spasms, microvascular angina, Prinzmetal's angina, angina inversa, stable or common angina, unstable angina and variant angina. Angina occurs when the heart muscle does not get the blood it needs to function properly. This usually happens because one or more of the coronary arteries is narrowed or blocked, also called ischemia.