"Sounds like your intermeiate
"Sounds like your intermeiate shift cable is starting to sieze up.
This is the short cable that runs from the shift quadrant to the leg. When it becomes hard to move, there is a delayed action in both the shifting process and in the cutout switch that is installed to allow the engine to momentarly stall in order to relieve pressure on the shifting mechanism . Hence your boat is stalling and hard shifting. Without this momentary stall it becomes very difficult to disingage the gears.
Replacment of this cable is not as straight forward as one could hope , but with proper information and tools it can be done by most.
Or if uncomfortable with this job, allmost all marine mechanics are fimilaur with it as it is a common problem.
best luck
B.J."