My heels hurt when I walk "far"

Pretty silly / I-should-harden-the-fuck-up topic but thought I ask.

In this case you may need to larden-the-fuck up. (if you are so thin that you do not have a pad of fat under your heel)

More likely is that you are just not conditioned to it. You got a bruised heel from a short walk because it is much more than you are used to. The body is built for efficiency, it doesnt do things it doesnt have to. It adapts when it is forced.

Walk more often and it will toughen up.

What is a bruised heel?

                                 A bruised heel can be caused by either a sudden impact (such as landing heavily) or repetitive pounding. The heel bone (calcaneus) is protected by a pad of fat. Repeated pounding of the heel can cause the fat pad to be pushed up the side of the heel leaving less of a protective layer causing heel pain. This injury is also sometimes known as Policeman's heel. It is common in sports requiring a lot of impact onto the heel and in particular soldiers marching up and down on the parade square.

If you get a non cyclist to do a days cycling, their muscles will be sore the next day.