Young people with numbness in the left hand and heart pain may be caused by the following diseases: 1. It may be caused by heart-related diseases. Contemporary young people, due to the fast pace of life, and often irregular work and rest, diet, often cause heart-related diseases, such as angina pectoris, myocardial infarction and the like. In the process of such disease, it may cause the heart or chest area of the crushing pain, and accompanied by the left upper extremity of the involvement of symptoms, such as pain, numbness and a series of symptoms in the left upper extremity. 2, this condition may be caused by cervical spondylosis, contemporary young people, due to the need for prolonged sitting and standing low, it may lead to excessive degeneration of the cervical spine, followed by cervical spondylosis. This can lead to excessive degeneration of the cervical vertebrae and subsequently cervical spondylosis. In the process of such diseases, it may lead to the irritation of the nerve roots, and then there may be radiating pain in the thoracic region and the left upper limb at the same time, and there may be symptoms of numbness in the left upper limb. 3, this condition may also be caused by the simultaneous onset of multiple diseases. For example, the simultaneous occurrence of heart-related diseases and peripheral nerve compression of the left upper limb may also lead to the above symptoms.