The most common cause of pain in the lower right side of the waist is chronic lumbar muscle strain, which is often caused by chronic aseptic inflammation and fasciitis of the lumbar region due to prolonged desk work, playing with the cell phone with the head down, frequent bending over for labor and housework. The appearance of lumbar muscle strain can be manifested as soreness and pain on one side of the waist, sometimes accompanied by spasm of the lumbar muscles, accompanied by stiffness of the waist. Treatment should avoid all of the above bad life and work habits, avoid frequent bending labor, avoid playing cell phone with head down, you can use anti-inflammatory, de-painting medication for symptomatic treatment, you can also use ethopiridol hydrochloride tablets to release the muscle spasm, at night, you should sleep on a hard board bed, not a very soft bed, and you can do lumbar stretching exercises.