What Causes Excruciating Pain In Neck And Back With Sciatica?

I have excruciating neck and back pain with sciatica. Can osteophytes at c5-6 which is causing moderate foraminal stenosis be the reason I have chronic pain? My MRI shows developmental canal stenosis at c5.as well as a small T2 signal change. PLEASE HELP!!!! How does all of this contribute to my neck, shoulder (spasms, muscle knots) and sciatica (burning pain left side, pins&needles in left foot)? Thank you so much!