I am sorry to hear about your situation an certainly know that it is not an easy one. As I imagine you have seen from my linked blog http://www.ledderhose.blogspot.co.uk
I also have Ledderhose but I live in the UK. A lot of the problem with this thing is jobs, I had a similar problem as I worked in scientific research which involves a lot of time on your feet and I struggled with that and dread to think what it must be like for you, I certainly know that with the pain I was in there is know way I would be able to do the job I used to do in a DIY store over here. Luckily I am moving into IT.
I also had a steroid shot but I had it into the lumps (ouch) and it seemed to help for a little while, at most 6 months but it is often considered by specialists not to be a great options. I would certainly recommend you see someone who knows a lot about this condition before getting surgery done on this condition, the heel spur might be ok but if the pain is coming from the lumps then getting that treated is not going to help. For this condition there are other treatments than surgery but the problem, particularly in the US is that they cost. I also have orthotics and one thing I would say is that although they help the stability of my foot they do not appear to be designed with the fibroma in mide. Have a look at them, they should have a dip in the middle so there is no direct pressure in the location of your lump(s) (normally in the centre of the arch) and they should also be quite cushioning so as to take some of the pounding off of your feet.
Radiotherapy is the option I have gone for, here it costs £2000 which I had paid for by relatives, but I think it is more than that in the US. This treatment does work for most people though and I am already starting to feel the benefits and I have not even finished the full treatment yet and I have interviewed the specialist treating me http://ledderhose.blogspot.co.uk/2012/07/interview-with-richard-shaffer.html
. I know another option that I have seen available in the US is cryosurgery where they super cool it and this helps stops the pain http://ledderhose.blogspot.co.uk/2012/07/interview-with-dr-spilken-cryosurgery.html
I am afraid though that for me the best medicine has been keeping off of it and I am lucky in some ways as although I got it young this has allowed me to change careers before it really matters (I'm 25).
I hope that you find talking to people is a help and hopefully you can find something that works for you.
I also recommend visiting the Dupuytren's online forum - there are loads of people with this condition there and they are more than willing to help, quite a few in the US as well I think. http://www.dupuytren-online.info/Forum_English/board/ledderhose/index-1.html