I need to itemize because I have business rental income with expenses. But when I enter expenses and save a copy of my return, it shows the std deduct in line 8. Why?

Rental expenses go on schedule E and have nothing to do with Itemized Deductions on schedule A.  Rental schedule E goes to the new Schedule 1 line 17 then to 1040 line 6
<a rel="nofollow" target="_blank" href="https://www.irs.gov/pub/irs-pdf/f1040s1.pdf">https://www.irs.gov/pub/irs-pdf/f1040s1.pdf</a>

You do not need to itemize because you have business and rental expenses.  Business and rental expenses are deducted on Schedule C for business expenses and rental expenses are deducted on Schedule E.  Business and rental expenses are not deducted on Schedule A Itemized deductions that is why your return shows the standard deduction