Hidden pain in the lower left corner of the waist may be caused by physiological factors such as exertion, trauma, lumbar myofasciitis, urinary system diseases and digestive system diseases. 1. Physiological factors: most often seen in the stooping labor lead to the accumulation of lactic acid in the muscle or sleeping posture is not correct, resulting in lumbar muscle spasm, tension, can appear in the lower left corner of the lumbar hidden pain. 2. Trauma: due to trauma and other direct violence to the lower left side of the waist, resulting in patients with the lower left corner of the waist muscles, fascia and other soft tissue injuries, can lead to the lower left corner of the waist hidden pain. 3. Lumbar myofasciitis: due to long-term work and other factors lead to lumbar muscle, fascia and other tissues of aseptic inflammation, can appear lumbar lower left hidden pain. 4. Urological diseases: including left urinary stones, urinary tract infections and other diseases, can cause the left lower corner of the waist hidden pain. 5. Digestive system diseases: part of the acute pancreatitis and other diseases can also cause the back of the back pain, can appear waist left lower corner of the hidden pain. There may be other causes of pain in the lower left quadrant of the waist, it is recommended to go to the hospital in time to improve the examination to clarify the cause of the disease, to give targeted treatment or treatment.