Why is it all of a sudden very difficult to shift the car into/out of all gears? on 2003 Hyundai Elantra

I had the radiator replaced and an oil leak repaired 3 days ago and the problem with the shifting began suddenly today. turning the wheel is slightly more difficult than usual but not very noticeably. could this just be that the car is low on power steering or transmission fluid?

Asked by for the 2003 Hyundai Elantra
Turning the steering wheel and has difficulty,can be low on power steering fluid, Now when you say shifting difficulty are you a automatic transmission,or manual,if your manual you may need a clutch master or a slave or even both, and yes this can leak also.