93 Mazda MX-6 shift stick?

[-ve zone]

Yesterday, my baby Mazda MX-6 got stocked on the high way, its a manual car. I was at gear 4 when off a sudden the stick retrograded to neutral and a large sound came up, the car stopped on the right hand side of the highway. the engine will start but the gear box was stucked, it wount let me enter gear one nor reverse to move out of the way.
I had to get a tow truck take me out of there. so please can any Mechanic tell me what might be the cause, PLEASE. need to go to school. the tow truck guy emptied me yesrteday just to get me home. lol