central disc protrusion

I had a cervical fusion with a fibular strut graft and anterior compression plate with srew fixation at C6-C7done in 2004. I have been having neck & shoulder pain with tingling in hands so the doctor ordered a ct scan. Please explain the impression.. Central disc protrusion at C4-C5 and C5-C6 measuring 4mm. Causing compression of the anterior thexal sac and abuts the cord at both levels. There is mild bilateral uncovertebral joint spurring at C5-c6 without significant neural forminal narrowing. The pain has developed in the past year. I have had cervical facet injection 3 times with no relief. I am most irritated performing my work duties. What causes these symptoms? is this a progressive matter? Please help me understand and what treatments can I got at work and hom.
Thank you