I have bulging herniations in my lower back (L4/L5 and L5/S1) and neck (C3/C4), and I have an inversion table, I use Teeter brand. It helps me, but I use it sparingly, as I'm concerned about too much inversion and the consequences that can have for capillary damage in the brain (I'm over 50).
Two things affect my neck more than anything - my posture (especially when reading, using my tablet/smartphone, etc), and my sleeping position. One I have immediate control over, the other one, not so much. I recently got a memory foam pillow, though, and that seems to have helped out a lot with the sleeping position issues.
I use one of those inflatable horse collar pillows when I fly. I look like a nerd, but f*** it, I need the neck support. I've thought about getting one of those foam neck brace collars, if for no other reason I can scam my way into early boarding. But I digress....
This is a very touchy subject, because the variables are so many, and everything is so individualistic. You need to learn as much as possible about what your specific condition is and learn what works best for you and your life.
Hope this helps