Ssa1099 lump sum for a previous year included. Can I enter it all on 2017? Do I need to amend 2016 or will it be taken care of on 2017 return?

If the lump sum payment is shown on the SSA-1099 for 2017 the TurboTax program will ask about lump sum payments when you enter the SSA-1099

Almost all taxpayers are calendar year filers and cash-basis - not accrual. You report income and expenditures in the year the transaction occurred.

Payments for income of prior years but received in a following year are reported in the year received.  This should be represented in the SSA-1099 that you have received (yes, they are already sent).