I see this all the time @ work, so I'll throw a comment in, but see my sig for the disclaimer.
Did you get a Trial modification or a permanent one? Trial mods mean squat. BUT, if you got a permanent mod after your BK, you may have inadvertantly reaffirmed the debt anyway. (Basically, if you signed new mortgage docs w/ new terms, its a new loan). I hear this varys from state to state, but you'll want to check. Our firm does it's best to get the loan mods done at least a few months before the BK, so the loan isn't reaffirmed when the mod docs are signed.
The best way to look at this is to think of a Loan Mod as a refinance, but you keep the same loan # and lender. If you do a traditional refinance after the BK, invariably the new loan was completed after the BK petition.
If your modification was fairly recent, you might want to wait a tick and see if it corrects itself. Otherwise you can dispute with the CRA's, telling them it wasn't IIB (only do this if your mod reaffirmed you).
A lot of this varies from state-to-state, so you might want to check w/ a good attorney in yours. Here in NV, if you include a 1st mortgage in BK, but keep paying it, the bank can't take the property back regardless of reaffirmation. (They need to foreclose to clear the title.)
If you have any more questions, let me know, I'll do my best to answer them, but again, see my disclaimer, below. (Our firm handles Loan Mods, Short Sales, Debt Settlement and BK, so I really have seen this alot, but I still can't give legal advice on a forum, everything above is simply my opinion).
-SM
Starting Score: ~470 preBK(8/2010)