It sounds like nerve pressure -- perhaps you can adjust your bar or saddle a bit (tilt, slide forward, backward) to alleviate the pressure points between your hands and bar. I developed a similiar problem several months ago, and it was caused by my old worn out saddle gradually tilting forward a bit. After a few months it had tilted a couple centimeters forward, and that caused the same symptoms you described. After I levelled seat back to it's proper angle, the problem ceased.