You would have to file amended returns for those past years.

You do have until 4-15-2018 to do the amended return for 2014 to still get a refund from that year.

Don't worry as TurboTax can help walk you through the process, just make sure the 2014 is done first so that refund is not lost.  IRS will also pay interest on the refunds.

https://ttlc.intuit.com/replies/3288565