When I did mine, I just jiggled the swingarm while pushing out the bolt, and it came out.Does the linkage move when you remove the lower bolt? I tried to push the bolt out with thumb no go, I'm worried about the thread what's the best way to remove the bolt?
I'm assuming you have a centerstand on your bike. If so, there's another way to take the pressure off the bolt in the swingarm so you can remove the shock, if you aren't able to physically lift the wheel to take the pressure off the swingarm bolt. Go to the hardware store and get some of those wooden wedges they sell that help you install a door jamb. They usually come shrink wrapped in a package. Stack up some some small squares of plywood under the rear tire until the tire is close to sitting on them. Then use the wedges to fill up the remaining gap, until the wedges are touching the tire. If you drive the wedges closer together, it'll lift the tire with very little effort, until you relieve the weight on the swingarm bolt. You set the wedges, then pull on the bolt; if it's still too tight, tap the wedges a little closer together. If you go too far, pull the wedges a little further apart. With this method you don't have to hold the weight of the tire with one hand while manipulating the bolt with the other. It will also support the weight of the tire and hold it in the correct position for reinserting the bolt after you change the shock.
I use this wedge method when I change the rear tire on my bike. The wedge holds up the rear tire and takes the weight off the axle, so the axle is easy to remove, and it also supports the tire while it's meshed to the final drive so the tire is easier to pull free.
I've attached a photo of one of the wedges I use. It's just four of those hardware store wedges, glued edge to edge. Gluing them together like that creates more surface area for the tire to sit on.