Hi and welcome to the Spinal Cord C/D forum.
Sorry I do not have answers for you as I am not familiar with osteophytes....but if it is anything like the other conditions I am familiar with, the time frame may be different from person to person....no 2 people are alike to the extent they would have the same time frame or symptoms....
If you feel your Drs are not giving you all the info you need to understand what is going on, get another opinion and get copies of ALL your MRI's and other testing including reports.
Timeframe? -- normally, many years as a natural part of aging. In your case, who can say w/o more information?
Osteophytosis is a cardinal sign of osteoarthritis in synovial joints. The diseased joints here are probably the apophyseal (facet) joints on either or both sides of the affected level. A good spine specialist (not a surgeon or neurologist, but a board certified interventional pain physician) can make this diagnosis with physical exam and MRI.
Osteophytes can cause pain by placing pressure on nerve tissue, for example, pressure on the spinal cord or nerve roots through "spurring", or from the diseased joint itself. If this is truly degenerative disc disease, pain can come from the disc itself, from extruded disc material, and endplate sclerosis (with which narrowing of the disc space is noted in an axial x-ray).
Regardless of the type of underlying disease, cervicalgia or cervical osteoarthritic pain can come on very quickly -- sometimes overnight. For instance, a person diagnosed with cervical degenerative disc disease or spondylosis can wake up one morning with sharp, severe pain in the neck, shoulder, and arms when the night before they felt only mild, nagging pain.
Pain does not grow up or down an extremity in these situations like some kind of creeping bacterial infection. Pain occurs in osteoarthritis from the joint and surrounding tissue, along with inflammation. Other sources of pain can be from foraminal or spinal stenosis.
Find a good spine doctor with an ABPM certification (DABPM) for a proper diagnosis and treatment options.