Can you deduct chapter 13 bankruptcy payments? If so can you go back and amend past income tax returns?

Federal income taxes paid are never a deduction from income, regardless of how or when they are paid.

However, below is a list of some of the items that may be deducted on your personal income tax return. 

State income taxes are deductible from income, in the year paid, for purposes of computing your federal income tax for that year, if you itemize deductions, on Schedule A.

Legal fees are generally deductible, on Form 1040, if they meet one of the three requirements:  

1. To produce or collect income that must be included in your gross income, 
2. To manage, conserve, or maintain property held for producing such income, or
3. To determine, contest, pay, or claim a refund of any tax. 

To deduct legal fees, you must itemize deductions on Schedule A, and the sum total of your miscellaneous deductions including your legal fees must exceed 2% of your Adjusted Gross Income.

Mortgage interest:  If your Chapter 13 plan is catching up on delinquent mortgage payments, the claim of the lender is probably mostly interest.

Property taxes paid through the plan should be deductible.  

Business expenses:  If you operate a business in Chapter 13 or operated one before you filed, you may be paying business leases, sales taxes, or vendor debt through the plan.

Spousal Support or Alimony

***You can go back and amend your income tax return(s) for up to three years, to get a refund. For additional information, click on How do I Amend (Change or Correct) a 2014 Return in TurboTax?

Basically, it depends on what the payment is for specifically, as to weather you can deduct it or not.

It's for various things like vehicle, mortgage arrears, credit issues almost to the end of 5 years for it to be discharged.  Also, lawyers, trustee, probably judge, court etc.