To be safe, use this IRS web site,
https://www.irs.gov/help/ita/do-i-need-to-file-a-tax-return
Or, prepare your return in Turbotax and let the program tell you. If you owe no tax and are not getting a refund, you can skip the filing step and you won't pay anything.
If you did not receive the $1400 "round 3" stimulus payment in the Spring of 2021, the only way to claim it now is to file a return even if you owe no tax.
If you are single, your social security is not taxable as long as half your social security plus your other income is less than $25,000. Since your pension is less than $2000 and the maximum social security benefit is around $30,000 (more or less), it would seem unlikely that any of your income is taxable. But the only guaranteed way to know is to check the IRS web site or prepare a tax return and see what it says.
