you're fine on the 58. I'm about the same height and can ride anything from a 55cm to 59cm top tube. Change stem, bars, seatpost to fine fit.

What part of your hand is killing you? If your feeling too stretched out, I'd run a 10mm shorter stem in the same degree you have now OR shallow drop bars with a shorter reach (can buy back 5-10mm or so here). You might find more comfort in a bar change. Most OEM bars are junk anyways.