Originally Posted by headwind15

This is just my opinion. I do not think that your frame size has anything to do with neck issues(s). My opinion is that it's your A) posture Your head looks like it might be craning forward a bit. Your back has a bit of hunch to it. Could very well be weak neck muscles, and they are being put to the test when being into the bike riding position/posture. I think hat you should try neck bridging (strengthening) at least three days a week to see if that helps. Also unrelated your seat may be able to go a bit higher.