If you're going to spray a solvent in there, I'd probably set the bike back down on the side stand and spray the solvent in from the uphill side. Gravity will be your friend, and help the solvent penetrate further. I usually use PB Blaster when it comes to a stuck part, and if it's stuck this bad, I'd spray it and let it sit for an hour before I tried whacking it again; let the solvent do its work.
This wouldn't be the first time I've heard of an axle seizing to a wheel. I got in the habit of smearing my axles with anti seize before I reinstalled them.
"No matter where you go, there you are."