Most of the pain when straightening the back is caused by lumbar spinal stenosis. In lumbar spinal stenosis, there can be herniated discs, hyperplastic bone spurs, and hypertrophic ligamentum flavum, and these pathological changes lead to nerve compression and symptoms of claudication or lumbar pain, especially the hypertrophic ligamentum flavum, which can make the ligamentum flavum compress the nerve forward when straightening the back and lead to increased lumbar pain. This is a characteristic of lumbar pain in patients with lumbar spinal stenosis. In this case, X-ray, CT and MRI of the lumbar spine should be performed for diagnosis, and early treatment should be carried out after diagnosis to avoid prolonged straightening of the back and early treatment such as nerve nutrition and physical therapy. If the lumbar pain continues to worsen, surgery may also be considered.