4+3 shifting issue

[Gary87]

I have an '87 coupe with the 4+3. This morning on the way to work I noticed that the transmission would not shift in or out of any gear without an extreme amount of pressure on the stick. Needless to say, I barely got the thing home. Oddly enough, the clutch seems to work fine and the car does not roll when the pedal is depressed in gear. I called the local Corvette center which incedentally had put in a new clutch kit, resurfaced the flywheel and serviced the transmission and overdrive last August. They said they could't help me without looking at it. Do you think my problem is the result of work they did, or is it something else? Any help will be appreciated.

Thanks,
Gary