I developed them when I was young. They are only a problem for me in some shoes; generally shoes with a stiff plastic heel counter. Even then, it depends on the shoe.
For shoes that are a problem, I use a sharp razor blade to slice open the back of the shoe over the bump. Be careful to not cut through to the fabric on the inner side of the shoe. (If you cut all the way through, the fabric will quickly ball-up, wear-out, etc.) I then sometimes use the handle of a small screw driver to push the plastic out.
Note that the plastic in heel counters is generally heat moldable. So you can also try using a heat gun to heat the plastic, then push an accommodating bump into the plastic. But, you will risk melting the fabric... Proceed cautiously, and try this on old shoes first.
[/img]
2015 USAT Long Course National Champion (M50-54)