Chest pain and spitting with light red blood may be caused by trauma, respiratory disease, cardiovascular disease, gastrointestinal disease and other reasons. 1. Trauma: If the chest is hit by external injuries such as impact, it may cause capillary rupture of lung tissue, which may manifest as chest pain and hemoptysis. 2. Respiratory diseases: such as lung cancer, due to the invasion of cancer cells into the blood vessels, resulting in blood vessel rupture and bleeding, which may be manifested as chest pain and spitting with light red blood. 3. Cardiovascular diseases: such as pulmonary arterial hypertension, which can involve the blood vessels in the lungs, and may present with chest pain, hemoptysis and other symptoms. 4. Digestive tract diseases: such as reflux esophagitis, when the gastric contents containing digestive juices reflux into the esophagus, can stimulate the pharynx to occur mucosal congestion, edema, may appear chest pain, sputum with blood phenomenon. It is recommended that people with chest pain and spit with light red blood go to the hospital in time, to clarify the cause of the disease, and standardized treatment under the guidance of the doctor.