I had it (time: for about half a day to a day) after +100km rides before I had my bar raised (using a steeper angle headset). I could not shift anymore, particularly from the small ring to the big in front.

See if raising your bar relieves pressure/makes you put less weight on your hands.

oh yeah. I also had it once after playing SimCity for 4-5 hrs straigt because I had my left hand rested on the edge of the table. It went away after a couple of days.