Back pain when bending can be caused by the following causes: first, dorsal myofasciitis, dorsal myofasciitis can be caused by cold, exertion, when bending over to hold things or bending over to work there is obvious pain, the pain is more obvious in the morning, after a period of activity can be improved, then early examination and examination, to exclude other diseases to diagnose. Second, rheumatoid, when rheumatoid involvement of the spine, can lead to back pain when bending, this time to check the spine X-ray, CT and blood tests to diagnose. Third, ankylosing spondylitis, ankylosing spondylitis can involve the entire spine, can lead to pain in the sacroiliac joints and morning stiffness, pain worsens in the morning, then to check the blood tests and take X-rays of the sacroiliac joints, spine, CT, MRI to diagnose, early oral medication, if necessary, to the Department of Rheumatology and Immunology consultation and treatment.