In your case, it seems you are not getting adequate care. I pray to god you are a long term pf-sufferer. I hope you are not having surgery, multiple shots, filing down spurs, etc. after only a few months.
Yikes, where to start. You are the perfect case of someone in dire need of heelspurs.com.
1) Read Scott's book on the site.
2) I would say get another podiatrist right away. The cavalier manner in which the doctor is sticking needles in you, cutting this, filing that, is-- I hate to say it-- SCARY! Cortisone has side-effects which may even include weakening the tissue it comes in contact with. When the dust settles from all this and you are better, you are going to have to strenghten and stretch your foot regularly to keep off new problems which may arise.
3) Orthotics help many people, especially if they have irregular feet, but not limited to that population. Others (like me) get worse from orthotics. Others get several adjustments or get several new pairs before they find what works. In any case, you can't just slip orthotics in and wear them all day. Your feet have to gradually adjust and I recommend a far more conservative break-in period than podiatrists generally recommend (you doctor did tell you to wear them a little at a time at first, right?). Orthotics can have side-effects too, though no one tells you that. (We discover things like that here).
Many, many are helped by Birkenstock classic footbed sandals like 'Arizona' and 'Milano.' I recommend buying a pair immediately. You might wear these in the home (AT ALL TIMES!). No barefooting, and you even need shower sandals too. Scott has several suggestions on over the counter inserts which you might try as well.
Orthotics are shaped to your foot so adding any heel lift would alter them. Do not add anything to orthotics. Heel lifts are to use instead of orthotics and have helped some. The best kind are 'viscous' or 'visco' heel pads, which refers to the clear rubber-like substance it is made from. You might try cheapo ones first just to see if your foot likes the position it is in, and then upgrade to viscous heel pads later (about $30-50). Always wear two of everything.
Don't have any more surgery until you've tried the other options, of which there are about a hundred.