4. Fractures
Another common cause of lower left back pain could be caused by a fracture. Vertebrae may be broken during an accident or a simple fall.
Most of the time, a fracture will develop in the lower back as the result of a disease that causes the bones to become thinner. This type of bone-thinning disease is called osteoporosis.
A person who is suffering from osteoporosis may develop fractures in any of their bones as they age and their bones become thinner. With time, the vertebrae of a person who is suffering from osteoporosis may even crumble. When this occurs, a person may experience pain any time that they move in certain ways as certain movements can cause the bones to compress the nerves.
The pain may be experienced in the lower left part of the back or even down the legs. Osteoporosis increases the risk of bone breakage, which is why people who suffer from this disease need to be extremely careful.