Does it have one servo or two? If it is two, is your electronic mixing set to control the second servo?

If one, check it with the wing off. Is it still binding?

Do you have the control horn on the same place on both ailerons? If it is forward or back on one, it will not move the surface the same. Also, is it on the same spot on the servo arm?

One other thing, take the controll rods off the ailerons and make sure the hinges are loose on both. you may have gotten glue on one side and locked the hinges. Just a though.

Hope one of those helps. Let me know what system you are using if one of those don't. (2 servos or one)