I show a qualified business income deduction but do not own a business, am not self-employed, did not file a Schedule C. TT said it was because I owned stocks. ???

Per the definition below from Congress of what is included in the Qualified Business Income deduction calculation, one possibility is if you received a 1099 DIV with an amount in Box 5, the dividends from a REIT can be included in the calculation.

Per the IRS recently released Notice 2019-07, the following is a definition of the income included in the QBI deduction calculation: 

Congress enacted section 199A (the Qualified Business Income Deduction) to provide a deduction to non-corporate taxpayers of up to 20 percent of the taxpayer’s qualified business income from each of the taxpayer’s qualified trades or businesses, including those operated through a partnership, S corporation, or sole proprietorship, as well as a deduction of up to 20 percent of aggregate real estate investment trust (REIT) dividends and qualified publicly traded partnership income.

Here is more information about the Qualified Business Income deduction:

https://ttlc.intuit.com/replies/7019998