Well tom, its funny to me reading your post because I felt exactly the same way as you at 3 years (got down a few scales, chords, can solo good). It is definently frustrating.
I feel now, two or so years later, that my playing has improved much due to a few things, including playing along with more people and more recordings, listening to as much music as i could cram in my head... but primarily by simple expirementation. I will try to explain how my playing evolved:
for a very long time i could only solo in the Pentatonic and blues scales, although i had it down across the fretboard. However I began to notice more and more that some songs became easily boring or even didnt sound so good as I soloed in pentatonic. So i basically cleared my head and decided that if i wanted somethign newer and more interesting, i would have to... forget the scales. Or not so much forget them, but enhance them. With ever song I put often (quite often Jerry and the dead or perhaps Phish) I would mess around with notes that were outside of the pentatonic and blues scales. Some were evidently out of key, but others fit strangely, a new sound for me outside of the blues scale. I began to incorporate these "new" notes into my blues scale until i had essentially reinvented it in my mind (i am sure there are names for these scales and such, but it felt great just to figure them out).
anyways, i slowly began to recognize how different sounds of songs (Major or minor for instance) fit better with my different "new" scales. trying out all these new notes felt great and sounded sooo new to me. The more i played with them to more proficient I got and the more I could place one "scale" with one particular sound in anysong.
So what am i really saying... play outside of your box of comfortable notes, and mess around to see what sounds weird and cool and strange and new and GOOD.