Why do I have to pay medical bills from my $10,000 auto accident settlement?

If you have a settlement, that settles all the claims you have, including claims for medical expenses, compensatory damages, physical damage and pain and suffering.  If you are offered a settlement and accepted it, then the insurance company is paying you for all claims.  You should not be negotiating a settlement in an at fault accident without obtaining advice from an attorney.  IF the BI limits are $10,000 that may be all the insurance company for the at fault driver can or would pay.  If you already agreed to settle, then there may be nothing more that can be done if you signed a release.  IF you settled, then what you owe your chiropractor is between you and that chiropractor.