Originally Posted by
10 Wheels
You have a good bike.
Now get your body in shape to enjoy it.
This.
If you want to spend money on the equipment side of things, going in for a bike fitting could be worthwhile, if you're not comfortable on the bike now.
Also, swapping out to 28mm tires isn't going to improve your comfort much, unless you reduce the pressure you run. The main reason wider tires are more comfortable is that they allow you to run lower tire pressures, so you might want to look at what air pressure you're using.