Sleeping on the left side of the heart uncomfortable may be related to the sleeping position, but also with coronary heart disease, heart valve disease, shingles, pleurisy and other diseases. 1. Long time to keep the left side of the sleeping position is easy to cause the pressure part of the blood flow is not smooth, there will be arm numbness, shoulder pain, heart vaguely feel uncomfortable performance. 2. Mitral stenosis, aortic insufficiency, coronary heart disease and other heart diseases patients in the left side of the bed may induce palpitations, chest tightness, anterior region of the heart pain and other symptoms, or due to psychological factors, conscious of the left side of the bed will be oppressed to the heart and feel uncomfortable. 3. Herpes zoster, pleurisy and other patients sleeping on the left side due to compression of the lesion area, which will cause pain and discomfort in the area, mistaken for cardiac discomfort. It is recommended to change the position of the body when sleeping and avoid keeping side lying for a long time. If the sleeping position has nothing to do with cardiac discomfort, it is recommended to consult a doctor in time to clarify the cause of the disease and target treatment.