What is the pain on the left side of the waist? The most common cause of male lumbar pain is fasciitis of the left lumbar muscle. Sometimes it has something to do with the working posture and the working sitting time. Some people sit in an incorrect posture, not sitting upright, always hunched over, hunched over, and lasted for a long time. In this case, it is easy to lead to such aseptic inflammation as muscle strain and fatigue, It can lead to left side lumbar pain, which is a common cause. The treatment is to correct sitting posture, reduce sitting time, and relieve inflammation and pain by externally applying some plasters, ointments, and taking some anti-inflammatory and analgesic drugs. You can also do some proper actions to exercise the strength of the waist and back muscles, lying on the bed with your head cocked up. Of course, there are other problems besides the pain in the left side of the lumbar spine, such as lumbar disc herniation, spinal canal stenosis, lumbar spondylolisthesis, and so on. These problems cause pain symptoms caused by the compression of the lumbar nerve root, as well as lumbar osteoarthropathy. Some people have a lot of bone spurs in the lumbar spine, which can also cause pain in the left side of the lumbar spine. Of course, besides the left side low back pain, is it possible that there is a problem with the left side of the kidney and urinary system. In addition to whether there is urinary system infection, some urinary system infections, urinary stones, tumors of the urinary system or retroperitoneal tumors may also cause left side low back pain. Others such as lumbar tuberculosis, suppurative infection, and some metastatic tumors of the lumbar spine may also cause pain on this side. Some elderly men have some severe osteoporosis, and some osteoporosis will also cause left side low back pain.