Sudden back pain and inability to bend may be due to injury to the lower back, such as when the patient is engaged in physical activity and sprains the lower back while bending over to carry heavy objects. In this case, the patient needs to rest in bed and immediately stop bending over to lift heavy objects. You can apply heat to the lumbar region or use acupuncture and massage techniques in Chinese medicine. The patient may have a history of lumbar disc herniation, and the moment he bends over, the herniation is aggravated and the nerves in the lumbar region are severely compressed, which leads to this symptom. Patients may also experience numbness and pain in the lower extremities, and in more serious cases, incontinence may occur, and patients should go to the hospital for examination in a timely manner, and it is best to take a CT of the lumbar spine to determine the severity of the condition in order to receive timely treatment. Finally, this condition may be caused by diseases of the urinary system, such as urinary stones, which can also lead to lumbar pain and inability to bend over. If a woman develops this condition during pregnancy, it may be an ectopic pregnancy and she should go to the hospital for examination and treatment in time.