That's a symptom of the issue. Could be your bushing is seized or nearly on that side keeping the grease from getting in. Of course even when new the greasing path was not sufficient/efficient and even if you'd been greasing it all along, it could still be bad by now.
As to the air, do anything you want, nothing to lose.
If I really wanted to grease it, I'd loosen the nut, remove the bottom shock mounts, and wheel, and work the arm up and down and sideways a bit. Probably should do that even if it were new. Then while still loose, try and get some grease in there. But it may just take the path of least resistance and come out the good side.
