I don't find Western saddles uncomfortable, I just find them all wrong for me. I can't feel the horse under me with all those pads, and Western saddles throw me into a position in which I don't normally ride. I'm constantly trying to put myself back into a proper English position, so am fighting the saddle the whole time. It's exhausting!
There's nothing wrong with using what ever saddle you like for trail rides as long as it works.
The "English" saddle was created by the Hungarian and German Cav to allow more flexability and variations with the things the Cav would be able to do. It initially gave them a desided edge over the Cav of other European nations. Later it was discovered that a major drawback to the design was that during campaign it caused a lot of horses to be out of action from sore backs. It doesn't have a good tree for the best weight displacement across the back. Cav's didn't want to give up the abilities that they gained from this kind of saddle though so it was a big problem during military compaigns trying to keep enough horses fit for duty available.
In the first half of the 1800's the British developed a new saddle design that allowed them to keep the abilities that the "English" saddle (that's not really "English"
) had made possible, but dramatically cut down on the numbers of horses with sore backs during compaigns (you'll always have some). The saddle eventually became known as the Universal Patern (UP). Some model/variation of it has been used by the military of all the English speaking countries except the US since around the 1850's. Today the design is more commonly known as the Trooper.
Now this does not mean that you will sore the back of your horse by riding your English saddle for pleasant weekend of trail riding
. Unless you're in the saddle for days riding a hundred miles or more a week for multiple weeks you're unlikely to have a problem (we'll take for granted that you have a well fitting saddle). Most people don't spend as much time riding as mounted troops on campaign. Working cowboys might, but then they'll be using saddles with trees that displace more weight than saddles with the English style tree.
Point being, ride what works for you and your horse. There's no right or wrong saddle if you just having a fun weekend riding trails. A saddle is a tool we use for riding. As long as the tool we are using allows us to do the job we want in the way we want with the results we want then it's what we want.