The following causes of left lumbar pain are common: 1. Postural causes: The patient maintains a sitting position with improper sitting posture, which overstresses the left lumbar muscles and can cause strain on the left lumbar muscles and produce clinical symptoms of soreness. The clinical symptoms are usually relieved by local percussion, and the correction of poor sitting posture can prevent the recurrence of symptoms. 2. Recovery phase: In the recovery phase of the left lumbar transverse process fracture, the clinical symptoms of left lumbar pain may also occur because the blood vessels have not yet fully recovered, and the patient will also have limited lumbar movement, and the presence of the fracture can be confirmed by taking X-ray films. It is important to diagnose and treat the left-sided soreness in the lumbar region at an early stage in order to obtain satisfactory relief of clinical symptoms in a short period of time.