Hidden pain in the lower left chest is still involved in the diagnosis and differential diagnosis of chest pain. The common causes of chest pain that we have can be divided according to the organs or according to the order of the chest wall from outside to inside, let’s say from outside to inside, we have localized pain in the chest wall. Localized pain in the soft tissues of the skin, such as neuralgia, costochondritis, and so on, and then to the pleura inside, then there may be pleurisy, and so on, and then to the inside, there may be localized pain in the lungs, such as pneumonia, pulmonary embolism, or tumors in the lungs close to the pleura that are causing the pain. Further into the heart, there may be pericarditis or myocarditis of the pericardium, or more serious myocardial infarction, angina pectoris, and pain in this part of the heart. Further to the side, there may be pain in the mediastinum or a rare organ of the digestive system, which causes pain in the lower left side of the chest due to involvement. Lastly, cardiac neurosis, which may be psychosomatic in nature, where there is no problem in itself, but the pain is self-perceived because of psychosomatic factors, is the main possibility of chest pain.