The awning arms should not stick. There should be space all around. If they are touching, causing the sticking, your awning fabric needs to be aligned square again. Basically, either the awning attached at the trailer has moved slightly, or the awning attached at the roller has moved slightly. When you retract the awning, it's not rolling up square, so the arms bend, causing them to not align correct, thus, causing them to stick.
Extract your awning. Get a carpenter's square and lay it against the trailer and the awning. Then tug and pull on the awning at the roller, where it slides into the groves, until the awning is true square again with the carpenter's square.
It takes some heavy duty tugging and pulling, but this probably the reason the arms are sticking. They all slide and move a little over time. I've had 3 travel trailers, and all 3 have needed some tugging and pulling at least once a year.