Something that very often works for me when attempting to remove stuck bolts, pins, etc:

In addition to using penetrating oil, I take a small ball-peen hammer and lightly "tap-tap-tap" the frozen part. Apparently, the vibration allows the penetrating oil to penetrate better/farther/quicker.

Obviously, YMMV, and if you're already T'd off (or it's not working for you), you run the risk of losing control and beating the snot out of it, and then regretting it. So don't DO that! ;-)) Just lightly.

Pop