Spinal pain in the middle of the back may be caused by lumbar muscle strain, lumbar disc herniation, ankylosing spondylitis and so on. 1. Lumbar muscle strain: lumbar muscle strain, also known as functional low back pain, is a kind of lumbar muscle and its attachment point fascia or periosteum of the chronic injury inflammatory disease, the patient can appear recurrent widespread low back pain. 2. Lumbar disc herniation: Lumbar disc herniation is a kind of lumbar disc degeneration caused by intervertebral disc fibrous ring rupture, nucleus pulposus prolapse of the disease, the patient may also appear on one side of the lower limbs or both lower limbs numbness, pain symptoms. 3. Ankylosing spondylitis: Ankylosing spondylitis is a chronic progressive inflammatory disease of the spine, and patients may have the symptom of spinal pain in the middle of the back, which tends to be aggravated when resting, and can be alleviated after activities. If the symptoms of spinal pain in the middle of the back persist, the patient should consult a doctor in time to identify the cause and under the guidance of the doctor for treatment.