This is a kind of problem which doesn't feel bad at all in the beginning. Its severeness only slowly grows until you suddenly understand that you really have a problem. Then it is much too late to be able to heal fast, and it's really difficult to rest the heel since you have to walk sometimes (resting e.g. an arm is much easier!). So my best advice is: don't neglect plantar facitiis-like pains in the heel, no matter how small they are! Get some help with it immediately, by finding someone who tells you what physio-exercises you may do, and what kind of foot supports you need (try for example the "air heel").