1997 Saturn SL1 Shifter stiff

I brought my car in to get fixed. They fixed the clutch and the master cylinder. The car ran great for about 15 minutes and then went right back to its old ways. It is extremly hard to get it into first or second gear. If I turn the car off it slides into any gear with no problems but when the car is running it is extremly hard to get it into gear. What could this be? I am worried it may be the transmission but after researching this seems to be a common problem with saturns and many people have suggested that it could be the pressure plate, the slave cylinder or the clutch Hydraulics. What do you think it could be?