Why there is no pain associated with mitral stenosis?

Mitral Stenosis: For starters, there are no specific pain fibers in the heart. When the valve is stenotic (narrowed) it impedes flow between the left atrium and ventricle. This causes enlargement of the left atrium and elevation of pressure in that chamber and pulmonary circulation. The symptom is then not pain but shortness of breath.

Pain not typical: Heart pain is usually associated with poor blood flow to the muscle of your heart. This can happen because of blocked arteries or thickened heart muscle from high blood pressure or aortic stenosis. Mitral stenosis usually doesn't cause the pumping chambers to thicken. Ms symptoms are usually shortness of breath and heart failure.