Yeah that's very true. I was at a concert that was fairly (very) negative music and I wasn't even opening myself up to the energy there and I got the terrible pain in my solar plexus. At the time I thought I was just really hungry but lately I know it is a sign of very dark energies manifesting in a space.

So if you feel that pain don't open yourself up further!

(I'm no longer head anger :p)

I guess a positive energy event would be a band like U2 where the music is more spiritual.