There is actually a lot of LGBT literature out there. There are various indie publishers dedicated to it. To find it, you need to look outside of the big book shops and mainstream literature and look into smaller publishing houses. The quality isn't always as good unfortunately - and my biggest peeve with them is that they often lack a plot beyond the LGBT aspect of the story. After you've read a couple dozen of them they all start to blend together.
One book I'd recommend is Edinburgh by Alexander Chee. But it is a heavy read. It's a coming-of-age story that focuses on a boy, Fee, who was molested as a child by his choir director, and how he grows-up struggling with the trauma from that experience. It spans across many years, starting from age twelve and continuing for over a decade, IIRC.
If you're more into fantasy / sci-fi, then I'd recommend the Wraeththu books by Storm Constantine. It's a post-apocolayptic story about a hermaphroditic race. The first book, The Enchantments of Flesh and Spirit, involves the protagonist, a human boy named Pellaz, being taken away from his family and being transformed into a member of this new race and his ascent into their hierarchy.
There are more I could recommend, but some of the scenes are incredibly explicit and I don't feel it would be appropriate to post them here. But if anyone's into fantasy I've got a great recommendation involving shape shifters - but I don't feel comfortable giving it's title out on an all-ages forum like this (so PM me if you're interested!). I also write LGBT stories and scripts, published under a pen name, and if anyone's interested I could put some of the unpublished cleaner ones up somewhere online to read for free.
