Hey, just read you other post, and it says your back hurts when you wear a bra - i pain i know well! If you're really really considering a reduction, then it might be worth considering seeing the doctors and tell them that you're depressed and in pain.
Other than that, a few things:
Get professionally measured and ask them to find you an appropriate bra. Marks and Spencers is the best for this! If your bra size isnt right, this will cause pain, coz you're not getting the right support.
Playtex for a range of bras called "just my style" which have Gel straps and gel covered underwires, and are designed for the D+ sizes. I have one, and its fantastic!
Triumph also do a really good range of bigger sizes which is fantastic for support - my best bra is a triumph.
Debenhams do both playtex and triumph in the bigger stores, so check there too.
Also, can I ask why you're posted as anon? its not that big a deal is it?