According to NetWellness, lower back pain on the left side is a common symptom of kidney stones. Kidney pain typically begins on the left side of the lower back and travels to the abdomen and trunk as the stones move through the urinary tract.
According to WebMD, pain on the left or right side of the lower back is also a common symptom of sciatica, a condition that occurs when the spinal nerve roots become irritated. Additional symptoms of sciatica include burning, numbness and leg pain that worsen when in a seated position. Individuals with sciatica may also have difficulty when standing up.