Cervical spondylosis is usually an age-related condition that affects the joints in your neck. It develops as a result of the wear and tear of the cartilage and bones are of the cervical spine. While it is largely due to age, it can be caused by other factors as well. Alternative names for it include cervical osteoarthritis and neck arthritis.

Causes -
Aging - Cervical spondylosis often develops as a result of changes in your neck joints as you age. Your spinal disks can become dry and begin shrinking around the time you turn 40, reducing the cushioning between the bones in your neck.

Cervical spondylosis can develop due to factors other than aging. These include:
Neck injuries
Work-related activities that put extra strain on your neck from heavy lifting
Holding your neck in an uncomfortable position for prolonged periods of time, or repeating the same neck movements throughout the day (repetitive stress)
Genetic factors (family history of cervical spondylosis)
Smoking
Being overweight and inactive