Re: Digging into the Fretboard
You need to have control when you play. Pressing too hard into the fretboard can make chords sound funny (because you pull the strings a little out of tune), and hitting the strings too hard usually causes buzzing (unless you have very high action). Your hands will also hurt much more if you're constantly grinding the string into the fretboard. Try forcing yourself to loosen up whenever you notice that you're grinding into the fretboard, and in a couple of months you'll be playing lightly without even thinking about it.
Dynamics and feel seems to me to come more from the amount of pick you use (Just the tip, slightly angled pick, picking deep into the string) to hit the strings than the amount of effort you use to slam into the strings. That said, make sure that you get your guitar set up to your liking - I find it easier to play with .11s and medium action.