Young people with vague pain in the left kidney should be alert to kidney stones, renal cysts, acute pyelonephritis, and local muscle injury should be excluded. For young people, if the left kidney is vaguely painful, the most common causes are the above three. Kidney pain caused by kidney stones is due to the pulling of the ureter by the stones, and the pulling of the renal peritoneum by the hydronephrosis caused by kidney stones, and it is also accompanied by hematuria in the naked eye. Kidney pain caused by renal cysts is due to larger cysts, resulting in an increase in the size of the kidneys, which pulls on the renal peritoneum. Kidney pain caused by acute pyelonephritis is caused by local inflammation on the renal pelvis, and also accompanied by fever, and sometimes accompanied by frequent urination, urinary urgency, urinary pain and other symptoms. If it is pain in the left kidney area, it is not necessarily pain in the kidney, it may be muscle pain. Especially for young people, sitting in front of the computer for a long time to work, due to the incorrect sitting posture, will lead to one side of the muscle stress is more obvious, it will lead to this side of the kidney area pain.