You received the lump sum in 2017? You report the SSA1099 on your 2017 tax return and carefully enter the information regarding the lump sum. You do not amend those past years.
Go to Federal> Wages & Income>>Retirement Plans and Social Security to enter your SSA1099.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**