HELP: Upper back/neck pain on rides over 60 miles

On long rides (60-100+ miles) on my road bike, I get an acute pain in my upper back, right on the spine, where that big vertabrae sticks out. Like straight down 5-6 inches directly below your hairline (normal, business haircut). The pain is on the left and right of that bone. I can ride my TT bike for 80 miles and never have this pain. But get on the road bike and I feel it after 60 miles. Is my stem too long? Am I too extended on the top tube? I would include a photo if I had one. I realize there’s not much to go on, but maybe someone’s had a similar problem and been able to fix it.

~AB~

I had the exact same pain. Turns out my road bike was to big, top tube to long and stem to long. Bought one size smaller frame and a centimenter shorter stem and that fixed everything.

I would recommend highly that you go to someone that does bike fits for a living to confirm this or something else but it sounds like you are too streched out based on what you listed above.