It's been my experience, changing pads over the years, that a lot of after-market pads are too thick in diameter and tend to bind. I even had to have a set of pads for a 750 machined down to fit. Weird that such a common part can be like that, and of course, usually all you can find is after-market. All you can do is check them against the original.
At least changing pads is an easy job. Good luck.