I just got back into riding this year and I was experiencing similar issues with my neck and hands. I have been riding now for 5 months and it has pretty much gone away over time. As skibender also said I think our bodies do strengthen and adjust over time. I also use gloves that have some padding in the palms. As BugDude also states I found that I could adjust hand placement and arm/shoulder position to relieve some of the tension and over time it comes natural and i don't even think about it.