Sounds like 2 problems, hard shifting has lead to no shifting.
Start by removing the shift lever plate on the left side of the trans case. You may loose a little oil, but not much. This is a simple shift fork arrangement that slides the PTO gear forward and backward.
Once it's off, you will probably find either a roll pin sheared or the lever is bent or broken.
Next is to determine why it broke. The gear that the lever moves should slide easily and smoothly by hand on it's splined shaft. If it is not movable, you will need to remove it and see why. This is relatively easy. It all comes out through the top. A manual will be very helpful.
Have you changed the trans oil lately? These are known for collecting water, especially if stored uncovered. It gets in through the shifter boots and the draft link boot under the seat.