As a rider with chronic neck, spinal column issues, it really is an ongoing process. After spinal fusion at C5/C6 in 2007, it was a long process finding comfort for longer rides. A fair portion of that was just time of recovery, a lot of it was trial and error trying to use small changes to get, at least, a good compromise. My issues/symptoms might be quite similar to yours, but my methods and results are likely to be different from yours. I wound up going back to a lower drop bar with a stem 10 to 20 mm shorter. Over the last 3 years I have shortened the reach a bit more. The other important thing for me is to change hands and body position frequently, including getting off of the bike more.