There are several possible causes of soreness on both sides of the lower back. The first is the fasciitis of the lumbar back muscle, lumbar back muscle fasciitis is common in patients who are cold, sedentary or bending over for long periods of time for labor, when the fascia of the lumbar back can appear, chronic sterile inflammation, which leads to pain on both sides of the lower back. The second cause is lumbar muscle strain, lumbar muscle strain can appear on both sides of the back lower back pain symptoms, in the morning when the pain is heavier, after a while of activity can be better. The third reason is the instability of the lumbar spine, the lumbar spine instability can also appear in the back on both sides of the lower back pain symptoms, then we have to carry out the relevant lumbar spine X-ray, CT examination to diagnose. The fourth cause is kidney deficiency, when there is kidney deficiency, can also appear lumbar pain, accompanied by knee weakness symptoms, then we have to carry out Chinese medicine pulse diagnosis, to carry out the kidney medicine treatment.