Hey, first of all four things that you should never skimp on: 1) Bibs/shorts, 2) shoes, 3) saddle, 4) Fit of the bike.

The touch points between you and the bike are a big deal. Having a hot foot is not fun. Your foot and your chosen shoe are probably not a good match. The Shimano SPD pedal has a pretty wide platform, but that really should not matter with a good shoe. I have ridden Sidi's (genius 5) for many many years and have had great luck with them. There are other good shoes too, the key is to get a pair with a stiff lower sole and some sort of durable (cork) midsole buffer. The stiff lower sole and cleat should go a long way in dissipating the touch points to the pedals and the cork should make the shoe comfortable over the long miles.

hope this helped

zac