Yes, both front and rear brake pads can be swapped out without removing the wheels. I've done that on a few bikes in the past. Not really hard, just need to be sure to insert the spring clips in the right place.
Yet another reason to own the service manual.
It could be that you simply need to spread the caliper halves. Push the outer half of the caliper against the disk and then let go to see if that helps. If not, inspect the pads (last paragraph below) to see if the pads are worn and need to be replaced. Ok, inspect anyway since you're looking at them. If they do then read on
First push or pull the calipers apart as far as you can by hand. The two halves of the caliper slide on pins.
Do NOT open the reservoirs to do this as you would then risk pushing out fluid resulting in dripping on the paint of the plastic.
Should be one pin that goes through the pads at the rear of the pad. Remove the cover screw and then you can remove the pin (threaded).
The new pads will be thicker than the worn pads you remove so after removing the old pads you may need to push the pistons into the caliper even more to fit the new pads.
There is a pad plate, thin metal, that should be placed on the back side of each pad. If the new pads didn't come with it I have been known to simply re-use the old plate.
Make sure the pad spring is properly in the front end of the caliper where the front of the pads will contact. There is a small tab on the pads that fits in specially to hold that end. I always fit the outer pad first, the pad that contacts the pistons. Once the outer pad is in place I fit the inner pad. If the space is still too tight for that pad to fit in I can push on the caliper to compress the pistons a little more into the caliper with the pad I already placed helping to protect the rotor from the pistons and also to provide extra spacing out of the caliper.
Once both pads are in place insert the pad pin through the caliper and both pads. I don't recall the torque spec for that so maybe someone else can post that information. Not too tight or it can break. Some silicone grease should go on the rubber O-ring on the end of the pin. Then replace the pad pin cover screw. (maybe the cover is not a screw but a rubber cover. don't remember now since some bikes have that and some have the screw).
Before you go to all this I would inspect the pads on the bike to verify if they really need replacing. In the photo below you can see both my worn pad that needed to be replaced and a new pad. On the new pad you should be able to see the notch where the pad material meets the backing. This notch is the wear indicator. If the pad is worn down to that notch, as in my worn pad in the photo, then it is time to replace. If you zoom in on the photo you may be able to make out the notch in the worn pad which shows just a tiny wafer thin edge of pad material remaining to expose the top of the notch. If ANY pad in a caliper is worn like that it is time to replace both pads as a pair. You can see this notch by using an inspection mirror (I've used my wife's makeup mirror at times
Don't tell please) and a flashlight. Look at it from the rear end of each caliper in line with the disk.
prior and current bikes:
1973 Harley Davidson 125 dual sport- sold
1997 Kawasaki Vulcan 750- sold
1990 Honda Gold Wing GL1500- sold
2005 Suzuki Burgman 650- sold
1998 Honda ST1100- sold
2014 Honda CTX1300A (U.S.A. Ion Blue Deluxe)-sn: 489 - sold
2013 White Suzuki Burgman 650 ABS
2003 Honda Metropolitan CHF503 (wife's ride)
flickr photos of CTX1300A
Yep, that lone state of Maine is where I owned my first mc.