trying to run a cost report. Report includes my SS but not my wife's. What am I doing wrong?

It sounds like you're trying to run some sort of "Spending" report, (Reports > Spending) though it's not clear which one.  "Cost report" sounds like you might select "Spending by Category" or "Spending by Payee", but since you state that you're seeing income in the report I'd think something like "Income and Expense by Category" might be more likely.

The typical reason some amount gets overlooked in any Report is that something is not being included in the report, such as the the Account, the Category, the Payee or the Tag.  So, for example, if it happens that your wife's SS is deposited in a different Account than the Account your SS is deposited to and her Account isn't included in the report, you won't see that income.  Likewise, if the Category you use for your SS income is different than the Category for your wife's SS income, but that Category isn't included in the report, then you won't see that income.

Click the "Customize" icon, (gear wheel), in the upper right corner of the report and check to see if you need to add a "missing" Account, Category, Payee or Tag to the report.