There are several possible causes of pain below the left side of the waist: first, lumbar muscle strain, when there is lumbar muscle strain can appear the muscle pain below the left side of the waist, often due to exertion, cold and caused, then to conduct relevant physical examination and examination to exclude other diseases for diagnosis; second, lumbar dorsal myofasciitis, lumbar dorsal myofasciitis patients can also appear the pain below the left side of the waist, then to conduct early physical Third, tendonitis, there is a tendon stop in the lower back, if long-term chronic pain in a location, consider the tendonitis and cause, then to conduct early physical examination and examination, early closure treatment.