Is there any theory behind what chords sound good in a progression? Or is it just a case of trial and error?

Also, lets say i was playing a chord progression starting with A, would that mean i would use an A scale for example A major to create a solo over it?

I would like to be able to start creating my own work but i've no idea where to start.

That looks like a great lesson Logz - I'll have a proper look at it when I get home

TS - I'd recommend you make sure you understand the major scale before you delve too deeply into modes. I'd learn how to harmonise the major scale by stacking 3rds, then go through Logz' lesson a few times Modes are derived from the major scale, so they make a lot more sense when you understand where they come from