I am self-employed and never received any tax documents that are asked for or required in filing, how would I go about finding them or seeing if there are any on file?

When you are self-employed you need to keep records of your income and expenses.  Most self-employed people do not receive any type of tax documents.  You can call the IRS and order a Wage and Income Transcript.   
IRS Phone Number | Call Now & Skip the Wait (gethuman.com)

hadn’t filed in yrs

I would highly encourage you to seek professional help to get your taxes current and up to date. TurboTax only supports their program for the current tax filing year (2020 until Oct 15th) and three years back. So if you haven't file taxes prior to 2017, you'll need to seek professional help anyway.

But either way, professional help is called for especially if your state taxes personal income. That's gonna be a double-whammy for you on back taxes and late filing penalties.

Do note that if you are due a refund, then their are no penalties. However, the IRS has a three year statute of limitations on refunds. So if you're due a refund for tax years prior to 2017, you will not receive it. However, that does not negate your requirement to file.

Please seek professional help yesterday, if not sooner.