Been playing for ten years now. I know close to nothing about theory. Most of what I know came from people here, so...stay around.

I've been writting songs for 5 years, but lack of theory kind of blocks me around some corners. You should get some basic knowledge but I am firm beleiver in music from the soul and not from the books.

I know Lalimace, you can still write music from the soul if you know a lot of theory :)

But always explore your guitar, try to get that "I don't know what I'm doing but I love how it sounds" and then try to know what you did with theory. That's how I work.