CATCHUP: 737 thrust levers can and do jam. This is due (According to Mr. Boeing) to the thrust levers, spoiler selector, flap lever and trim wheel all being mounted on what is for all intents and purposes a common shaft. We had just such an incident about three years ago (on the ground fortunately - the lever wouldn't advance much above flight idle), and the only way to clear the problem to disassemble things and fix what had gone wrong was to manually wind the trim wheel whilst heaving on the stuck throttle lever.
Wouldn't like to try that in flight.