What I have accomplished with guitar,and my next step ?.?

I have been playing for at least 3 years (maybe more) and stupidly never took a course never put my head in the books,never even learned names of most chords,or learned scales,and modes,or even how to read without tabs. I have the most fun with guitar when I'm making up my own songs. I listen and play mostly Metal,or ska/reggae kinds of music,and honestly with my ignorance of any kind of knowledge of the core academic parts of music I actually do pretty damn well,and can really shred some decent sounding riffs/solo's,but I'm unsatified with the fact I come up with songs and can't finish them,because I can't either link one riff to the next etc. At this point I can really move the fret board I feel if I can learn the fret board I will be a top notch guitar player. Where do I go from here ?.