Neck Soreness

This is a problem I have as well but not until about 3 hours. I thought possibly I needed a new stem. What I do is vary my grip often. If I stay in the drops too long it bothers me but I must be getting used to it because it doesn't bother me at all now so I am not going to bother with the stem.
You might do a search for proper fitting of bicycles. could be something simple. Nick

Just stretch it before, during and after, especially long rides. It helps in minimizing the soreness. Hope it helps

i have a well fit bike that i have been riding for years and one day last summer after a 4 hr road ride my neck/ shoulders
started killing me to the point i couldn't ride for more than
a hour or so. tried everything ,chiropractor's and the such.
until one day i saw my reflection in a window and realized that i was shrugging my shoulders. now i stretch my shoulder's then my neck after everyride, and really concentrate on dropping my shoulders during rides which keeps the tension at a minimum. this has helped
tarvy

Thanks for all the good advice.

i have also been having neck pain. i took my bike and myself in for 'measurement' and it turns out my handlebars are too wide for my shoulders. Am chaning them out for narrower ones so will see how it goes