Patients who suddenly experience pain in the back like a fork in the air are first likely to have a spontaneous pneumothorax. In patients with long and lean body types, spontaneous pneumothorax may be caused by strenuous activity, and the patient may experience pain in the chest as well as in the back, and may have difficulty breathing. Secondly, the sudden appearance of pain in the back may also be caused by muscle strain during strenuous exercise. If you do not warm up well before strenuous physical activity, it may cause excessive strain on the intercostal muscles, resulting in spasm of the intercostal muscles, which may cause back pain. Finally, back pain may also be caused by heart disease, such as patients with coronary artery disease may experience angina pectoris due to myocardial ischemia. In addition to the symptoms of anterior heart pain, patients may also have symptoms of back pain. Therefore, further examination is needed to clarify the cause of this condition.