Sleeping on the left side of the heart with a feeling of pressure and sometimes hidden pain may be caused by cardiopulmonary diseases, digestive system, neuropsychiatric diseases and other factors. 1. Heart disease: due to certain congenital diseases, angina pectoris, myocardial infarction, etc., can cause pressure or even pain in the heart during sleep, and it is necessary to go to the hospital for detailed examination of electrocardiogram, cardiac ultrasound, troponin and other items to clarify the cause. 2. Chest disease: lung lesions and thoracic lesions can cause stuffy pain in the anterior region of the heart, and it is necessary to go to the hospital for chest CT and other examinations to clarify the cause. 3. Digestive system: due to gastroesophageal reflux disease, gastric reflux stimulates the esophageal mucosa when lying down, which can also cause pressure or even pain in the heart when sleeping. 4. Neuropsychiatric disorders: Due to triggers such as neurosis, anxiety, excessive stress, and staying up all night, it can lead to discomfort in the heart. If the above symptoms persist for a long time, you need to consult a doctor in time to improve the examination and clarify the cause of the disease, and treat the symptoms.