If the doctor wants to give you a shot - where will he put it? Is he going to treat PF or TTS? The location of the shot would be different.
Do you trust the doctor?
Has he done this before (I assume so - if he's a podiatrist).
Are there options left other than the shot?
What are the risks?
Does he really feel it will help?
In my case, I decided against the shots - but I don't have your pain level either. Since September, my pain has only been 'out of control' for a period of couple weeks on and off during January. If I behave and don't do much, my pain level is usually manageable. I don't normally take any medication at all - so on bad days even one tylenol usually takes it down to a tolerable level. I have developed a very high tolerance for pain (compared to what I used to have and compared to what most people have) and I put up with an awful lot. That's not to say that's something to aspire to, or that it makes me a hero in any way. I simply don't feel as though I have much of a choice right now, and I'm not willing to just mask the pain until I know for sure that it can't be fixed.
In your case, it does not sound like you are able to get your pain down. There is only so much you can put up with, and it's terrible to think that you are living with such awful pain all the time.
Talk to your doctor about all your questions..you may decide to give this a try. A lot of people have been helped by a shot - and you're certainly not rushing into it without trying everything else. Please let us know how you do....take care.