I've been touring for around 2 months now and this problem just started to occur. It feels almost if there is a very tight band tied just above my cross-trainers (don't use cleats). A sharp pain, worsened as I bend my foot upwards, pointing my toes towards the sky. Usually starts occuring during the last part of the day. Any clues?

I had a similar pain, but you won't like what it turned out to be: Gout. Hereditary. Any family history?

Other than that, it could be your shoes are too tight. Or the wrong shape for your feet.. Check your shoes, and see a doctor.

Nope, no history. I think I'm way too young though. The pain goes away after 10 minutes when I stop.

Gout can hit in your teens and 20's. So - check your shoes. If they pinch your feet or compress them along a nerve, that would explain the discomfort. If so, the solution should be obvious - shrink your feet.

Ever drop something (heavy) on your foot?

I dropped a few 1x6x8 pieces of Oak on my foot last June, and am still feeling pain to this day. Apparently, I had a hairline fracture in my first metatarsal bone that never healed properly. I'm unable to walk properly and keep exacerbating the injury, which totally sucks because it cuts into the biking.

Get an X-Ray to see if there is some mechanical damage to the bones.