Sleeping flat on the chest with a feeling of pressure may be due to abnormalities in the psychosomatic aspects, such as anxiety and depression. It can also be a symptomatic manifestation of certain diseases, such as heart failure, myocardial infarction, lung cancer, gastroesophageal reflux disease and so on. 1. Spiritual and psychological factors: for example, if a person has long-term anxiety or depression, he may feel pressure on his chest when he sleeps, and he can slowly adjust his mind. 2. Heart failure: sleeping flat on the floor will lead to an increase in the volume of return blood, the left atrium pressure will rise, aggravate pulmonary stasis, and the diaphragm is up, breathing is more difficult, the chest may appear pressure. 3. Myocardial infarction: acute occlusion of coronary artery lumen, necrosis of myocardium supplied by it, chest tightness or sense of dying may occur. 4. Lung cancer: Cancer cells will invade the pleura, and the chest cavity will produce a lot of exudate bilaterally, which will cause dyspnea and a sense of pressure on the chest. 5. Gastroesophageal reflux disease (GERD): gastric acid refluxes into the esophagus, and due to esophageal spasm or dysfunction, burning sensation under the xiphoid process or pressure sensation in the chest may appear. If there is pressure on the chest when sleeping and lying down, you should go to the hospital in time to clarify the cause of the disease and standardize the treatment under the guidance of the doctor.