I've had some nice success with using NMT (Neuromuscular Therapy) protocols on my clients for their plantarfasciitis. It has taken one, maybe two treatments at the most, and then it goes away for about 1-2 years before starting to come back again. So, I've found NMT to be quite effective. In our school, though, that was taught only in the advanced courses (NMT was not part of our basic certification), but the NMT class was WELL worth the extra money.
Not to derail the original topic, but I have to say this about cortisone shots:
Please please please do NOT get cortisone shots in any joint! Yes, it will relieve the pain and inflammation symptoms for a while (the average I see every day is about four whole months), but it will not address the cause of the pain/inflammation, so the symptoms are guaranteed to return, and when they do, they'll be worse. This is because the condition has had time to further deteriorate and since the pain has been diminished during that time, the patient probably has not sought any legitimate treatment (legit = addressing the cause), and has instead kept using the joint in the same dysfunctional movement patterns that got them to that state in the first place.
The most important aspect of cortisone shots is that any reputable MD will only give someone THREE of them throughout their entire lifetime because of the significant damage each shot does to the joint, and any more than three will basically destroy the joint entirely.
NMT or other similar techniques is BY FAR the best way to go!
Hope that helps! Good luck with the issue, I hope it gets resolved.
Hugs,
~Jyoti