Left-sided back pain can be related to lumbar disc herniation or lumbar muscle strain, etc., while swollen and painful toe joints can be considered to be related to gout or rheumatoid arthritis and other causes. 1. Lumbar disc herniation and lumbar muscle strain: lumbar disc herniation is caused by degenerative changes of lumbar intervertebral discs, when the protruding nucleus pulposus presses on the nerve root of one side, it can cause one side of the back pain or lower limb radiating pain; when one side of the lumbar muscles or tendons are under too much pressure, it can lead to lumbar muscle strain, with one side or both sides of the back pain, and the pain worsens when exercising. 2. Gout and rheumatoid arthritis: the body’s high intake of purine, alcohol or drugs and other factors can trigger gout, patients can have redness, swelling, pain and dysfunction in the interphalangeal joints; by the immune factors or infections can be caused by rheumatoid arthritis, the patient can appear in the joints of the toes pain, swelling. Patients with back pain and swelling of the toe joints are advised to consult a doctor in time to find out the cause of the pain, and then treat the symptoms according to the cause.