2002 Mazda 626 shifting problem

I have a 2002 Mazda 626 with an intermittent shifting problem. Frequently the shifter will bind up and I can only get into 2nd gear. It seems the longer the car is driven the worse it gets. I have taken it into the dealership twice but they say nothing is wrong. I’ve tried contacting Mazda HO but they won’t do anything. What can I do? And yes all the fluids are fine and the engine is regularily maintained.

Standard or auto transmission?

Standard.