Let me help....Hold the club lighter within your hands. You may have read about Sam Snead's comparison of grip pressure as holding a baby bird in your hands, measure of pressure.
Maintain this lighter grip pressure at the start and maintained consistently throughout the entire swing.
Also check to see if you have excess wear on your lower right side of golf glove (for right handers).
If so, this indicates a change in your grip pressure somewhere in your golf swing.
A few last things to check...If you are taking large divots often, this will eventually cause pain. (You are overly steep in your downswing.)
As will constantly hitting off-center shots that seem to make the shaft reverberate in your hands.
A golf lesson would be in order to correct the last two issues.
Hope this helps!