I get stiff neck and also have gotten severe pain in my neck, which usually goes into my left shoulder and sometimes my arm. However, I do not have a diagnosis and never actually had it checked out via imaging. It comes on in flares; sometimes it's mild, sometimes it's excruciating. I also get severe spasms with it; at times my left shoulder will be in such spasm that it's actually like it's pushed forward out of place. Then the pain goes up the back of my head and I end up with a headache as well. I can't bend my neck nor move it side to side. I also have a huge stock of all kinds of heating pads, heat patches, rubs, and creams. I have a big moist heating pad that's for the neck and shoulders and it has a tie on the front so it stays on. I find the moist heat works the best, at least while it's on. I also have to sleep on a donut shaped cervical pillow, which does help lessen morning stiffness.
I have a history of lumbar spine issues, spondylosis, stenosis, herniations, etc...I noticed my Rheum has me down with a diagnosis of cervical spondylosis as well. With some of my symptoms, I wondered if I have something similiar going on in my neck as I did in my spine. But my lumbar spine was so severe, I only had that imaged and ended up needing surgery. At this point, though, with my basic insurance, I can no longer get any testing done so it may be some time before I ever actually get my neck thoroughly checked.