Try a Townie
I've had two spinal fusions - a two level back in 1993 and a single level in 2005. I started riding a bike again in 2008 using an old Schwinn Varsity from the early 80's, and my neck was hurting big time. The problem was that my riding position was not upright enough to relieve the pressure on my neck. My handlebars were too low, and they could not be adjusted enough to get me upright.
I went to my LBS here in Texas and the guy there immediately mentioned an Electra Townie. I did a test ride on it and a couple of other bikes (Trek Navigator and Specialized Expedition (I think it was) and the Townie was the only one that was comfortable. The others hurt my neck within 10 minutes. Their riding position, while fairly upright, was not as comfortable to me as the Townie. I have had the Townie for a year now and no neck pain at all.
I highly recommend the Townie for riders with neck pain. It saved me from quitting riding.