Chord progression, Scales, Diatonic, Pentatonic..dude..

Hey people I got a problem man... hope someone can help me out..thanks!

I can play chords, Like...Em,em,Dm,Dm,Fm,fm,...etc.. I don't get what are the 12bar blues,pentatonic, diatonic,scales..

I am really lost..I understand they are played because they sound good and you mix them up and add your own flavor to the solo... but what do they mean...like what is exactly a chord progression? like take...the chord... EM,Em,E7..I know that, but then it progresses with the chord progression?? no idea what it means...and the scales... they show the scale of C... is it finger picking on the strings till the 12th fret...but why its it called C..scale...and what do the names mean...?

Thoughts of a lost man. man... :/

This would be a great lesson to have on the site.

This is the closest I found to help you understand it. Hope this is what you're talking about.

http://www.all-guitar-chords.com/lesson.php?id=26