Muscle or ligament strain
Repeated heavy lifting or a sudden awkward movement can strain back muscles and spinal ligaments.
Bulging or ruptured disks
Disks act as cushions between the bones (vertebrae) in your spine. The soft material inside a disk can bulge or rupture and press on a nerve. However, you can have a bulging or ruptured disk without back pain
Arthritis
Osteoarthritis can affect the lower back. In some cases, arthritis in the spine can lead to a narrowing of the space around the spinal cord, a condition called spinal stenosis.
Osteoporosis
Your spine’s vertebrae can develop painful fractures if your bones become porous and brittle.