If the cables don't move free in their housings... There is probably some glue right at the opening...... You might have to remove the cables and clean out the hole a little with your hobby knife.... If they are free, then you need to adjust your linkages so that there is no binding. If you get some slack in one cable while the other is taunt, that's okay... In the air the taunt cable will keep the control surface deflected in the direction it needs to go....