Hi,
Marginal osteophytes at the cervical spine is seen commonly in spondylosis and when the facet joint of the spine which cushions the vertebrae loses its cartilegenous layer due to constant rubbing.
In some , this osteophyte will be completely asymptomatic however looks like in your case this is irritating a nearby nerve which travels to your arm hence you feel excrutiating pain in your arm.
Next Steps
While pain relieving medications will help you relieve pain, you need to see a physical therapist to do some neck strengthening exercises, stretches and posture correction advice in order to reduce the impact of the osteophyte formation on the nerve.Physios can also use TENS to relieve nerve pain in the arm.
Health Tips
Swimming is the best exercise..swimming in warm water will help you relieve spasm around neck and increase the neck flexibility which is usually lost in cervical spondylosis.
Hope this helps.Have a great day