Little Help

I've been playing guitar for quite some time now, but I'm confused on many things. I need some help with guitar theory. Like chord progressions, scales, keys, modes. If anyone could point me in the right direction it would be greatly appreciated. I like to play metal, but I enjoy playing blues sometimes and really anything that sounds good. I'm basically trying to find out when to use what scales in solos. Any information would be appreciated :) Thanks in advance.

The fact is so long as you stay in key, then you can play basicly any scale that accomodates the chord progression- Sticklers for theory can tell you exactly what should be used when, but I like to hear a more warped perspective when I hear a solo. This is music, so it's all up for interpretation.