Cessna 182RG pilot reported a malfunction with the flight control system. Pilot diverted and landed uneventfully.

Narrative

Activated Autopilot in heading mode; aircraft banked to the right; did not follow course line; ball in turn coordinator was all the way to the right. I used the disconnect switch on control wheel to disengage Autopilot; roll control felt stiff; aircraft began a flat turn to the left. I pulled the Autopilot circuit breaker; roll control still felt stiff airplane continued to turn left until I used a lot of right rudder. I [requested priority handling] with ZZZ ATC; ZZZ asked my intentions and I said I was going to land straight in on Runway XX. I looked at the flaps and ailerons on both sides it looked like the left flap was slightly deployed. I lowered the landing gear and applied 10 degrees of flaps; the flap application seemed to restore normal control. The landing and taxi were uneventful. After shut down I cycled the flaps several times and they worked normally in all three down settings and when fully retracted. I boxed the controls forward and aft; side to side in all positions; all was normal.The Autopilot (STEC 55X) was the initial cause of the control problem; after shutting it off it seemed that the aileron (roll) control stayed stiff as if the Autopilot was still engaged in roll. My thoughts were initially: 'there's a problem with the Autopilot; no big deal; just shut it off'. After turning it off my level of concern went up a lot; next thoughts were: 'I better get on the ground ASAP; there is something wrong with the flight controls' As of this time I do not know what is wrong with the airplane. An A&P/IA will be looking at it tomorrow.