Hidden pain on the left side of the chest when gasping for breath may be caused by heart disease, costal cartilage disease, lung disease and other reasons. 1. Heart disease: such as coronary heart disease, due to the narrowing of the blood vessels of the heart, when the patient’s activity increases, there will be insufficient blood supply phenomenon, which can lead to a vague pain in the left chest when gasping for breath. 2. Costal cartilage disease: such as costal chondritis, inflammatory exudate stimulation of pleural nociceptive nerve, can cause vague pain in the left chest. 3. Lung diseases: such as pneumonia, when gas tension in the pleural cavity is too large and pulls the pleura during gasping, vague pain in the left chest can occur. It is recommended that those who have vague pain in the left chest when gasping for breath should consult a doctor in time to clarify the cause of the disease and standardize the treatment under the guidance of the doctor.