Music Theory....Start where?

I've been playing for two years and have got all the basics down. I can read tab, play chords (barre and open), play scales from tab and some easy solos off of tab, but what does it all mean? I heard someone say once that music is kind of like math and I'm good at math but don't get music. Where do I start? I want to be able to write my own solos and be able to play with other people.

Reason people say music is like math is, because the basic properties of music have a lot of physics in it and some geometry. Making music itself has little to do with math in my opinion.

First off you can play scales off tabs, but can you play scales without it tabbed out in front of you. Do you know the relation of the keynotes to chords? How good are you at the techinque side of things. Can you keep a good steady even rythem. Can you play in weird time signatures? If you haven't got that stuff down you haven't finished the basics. You only know the introduction to the basics.

If you can do all that then it's simply a matter of how creative you are and if you can put what you know into action. application. It comes with experience.