ORIGINAL: scaminjs
I was going to take the aileron servo out and check the aileron arms because one seems a lot stiffer than the other, but it looks like the guy that I bought the plane from may have stripped the screws holding the servo in, so if the difference is not going to affect me learning on the airplane, I won't mess with it until I am ready to upgrade it to dual servos. Thanks again for the information.
You should correct the screws of the servo to make a solid attachement to the wing pocket; may be using longer screws and some CA.
Try to loose the arm that is stiff by disconnecting the assembly, moving it by hand and dropping some light oil into the guide if needed.
Then, reassembly as CGRetired has explained above.
Have an experienced RC pilot check your model before taking it off.
Check this article out:
http://www.masportaviator.com/ah.asp?CatID=2&ID=23