In my area of coastal New England we are able to ride all winter except when roads are covered with snow or ice. Consequently, winter mileage is much reduced compared to summer months. When I'm in good physical condition during the summer, I find I like the bars a bit lower than the saddle. When beginning riding during warmer months, my neck gets a bit sore so I raise the bars slightly. Surprisingly, just a cm or two up or down will make a difference to my neck. As mileage begins to ramp up for summer riding, I've found neck exercises are helpful. I suspect that as you develop your own riding and learn how your body responds, you will learn how to deal with the discomforts that can occur.

One piece of advice that is commonly given and which I've also found helpful is to learn to relax on the bike with minimal muscle tension in any part of the body except for those muscles necessary to pedal. For example, when the fit is correct, the cyclist will have some bend in the elbows with minimal effort exerted by the arms.