Originally Posted by Campag4life

We are close to the same height although I am lighter and have chased the same issue for the last couple of years. I haven't been formally diagnosed but no doubt the vertebra in my lower neck are marginal. There are a number of things you can do. I strongly suggest you experiment with your current bike set up before switching frames.
Consider going with a compact handlebar like the FSA Wing Compact and reducing your overall cockpit length. Also consider a narrower handlebar. What is your current head tube length?...spacer stack height?...and stem config? Are you running a riser stem? I am not a big fan of custom frames with the advent of upright bikes out there. You will want a head tube ideally in the 200-220 range. Mine is 170 + 15mm headset stack +40mm of spacers with a 10 deg flipped up stem. If I want to go faster, I flip the stem and take out some spacers but I don't notice much of a speed improvement as I now will use the drops more frequently and can still put my chin on the top of the steerer when descending if I want.
Lastly...consider two bikes. One for race day and a more upright bike to train on. Ultimately you and me as we age will likely end up on a quite upright bike with a swept back (Dutch) handlebar a la Rivendell variety. I bought a Nitto Albatross bar to experiment with. My issue is and no doubt you feel this way is...I am adicted to speed and like to ride fast. Catching more air is slower.
Best of luck...to both of us...Cheers.
PS: Lastly...a fellow neck sufferer will come along and say Recumbent. I am doing everything within my capability to stave off this dynamic. The thing is...they are right of course. Also no crotch rocket motorcycles for the same reason.