1994 Miata Trans aapprently stuck in 1st?

Weird one today... haven't had my Mazda 1800/5sp powered Lotus 7 replica out in a couple of months but needed to relocate it this morning in single digit temps to use the enclosed trailer it lives in. The car fired up fine but the shifter seemed stuck in 1st. Clutch hydraulics and clutch are fully functional (I can start and drive the car) but the shifter is frozen in place.  Rocking the car, popping the clutch, etc... nothing seems to make a difference. The day warmed up to near 30 but no change... Not intimately familiar with the Mazda transmissions except that in a replica 7 chassis it's the final component to come out when disassembling the car.  ;-)    ... Suggestions?

thanks!

Bill

My last Miata shifted really poorly when I bought it. When I rebuilt the shifter, I found that the lower spring had broken into three pieces and had fallen to the bottom of the turret. One piece was really small and I had to fish around with a magnet to get it out of there. I'd buy a shifter rebuild kit and start there.