Waist is known as kidney in medicine, so waist pain means pain in kidney area. There are many causes of kidney pain, such as lumbar muscle strain, kidney stones, pyelonephritis and so on. 1. Lumbar muscle strain: This is a chronic injury to the muscles, fascia, ligaments and other soft tissues of the lumbar back, which sometimes shows diffuse pain symptoms on one or both sides of the lumbar back. Due to the patient’s long-term sedentary or other lumbar muscle exertion habits, resulting in lumbar muscle overwork, which in turn produces strain, inducing pain in the lumbar as well as renal region. 2. Kidney stones: Kidney stones are formed by the high concentration of calcium, oxalic acid, uric acid and other soluble substances in the urine to form ever-increasing crystals, which are deposited in the kidneys. Kidney stones usually do not cause pain, but if the stone falls into the ureter or blocks the renal pelvis or calyces causing hydronephrosis or hydronephrosis, pain will occur. 3. Pyelonephritis:Pyelonephritis is a common upper urinary tract infection, which can be caused by various pathogenic microorganisms such as bacteria multiplying abnormally in the urinary tract, and manifests itself as bilateral or unilateral low back pain, with obvious pressure pain in the kidney area. There may also be other causes of pain in the kidney area, such as the kidney area may be traumatized resulting in pain, herniated lumbar discs compressing the nerves resulting in pain, and osteoporosis may also result in bony pain around the lumbar vertebrae. When kidney pain occurs, it is recommended to consult a doctor in time to clarify the diagnosis and give targeted treatment or therapy under the doctor’s guidance.