Check the belt tension? When's the last time you changed your serpentine belt and tensioner?
Another test is to jack it up off the ground and see how easily it turns, and then disconnect your steering links and see if your individual wheels turn freely. It's possible for steering components like upper strut bearings to wear out and bind completely, but that's pretty rare.
The steering U-joint on the engine side of the firewall started to go on mine 2 years ago. The wheel felt heavy with hard spots, especially in colder weather. The symptoms would lessen when ever it would rain. I replaced it and afterwards everything was good as new.:thumbup:
Then my steering rack took a dump 4 months later...:facepalm: