Inheritance stock and pension

Yes, if you have received a distribution from your mom's pension and it has been reported on a Form 1099-R under your Social Security number, then you need to include it on your tax return.  

For the stock, it depends on whether you inherited the stock shares on their own, or whether the stock was sold and you received the proceeds from the sale.  If you inherited the shares, then that alone is not taxable or reportable on your return until you actually sell the stock.  At that point, it is reported on your return and may be taxable depending on whether you have a gain or a loss from the sale.  

If the estate sold the shares and you received the proceeds from the sale, then the estate will report the sale and potentially pay tax on the sale of the stock.  You would not report the cash that you received.  

Take a look at the following TurboTax help article to learn more:

Is an inherited IRA or retirement plan taxable?