Yes, you will need to amend your return. The IRS will also get a copy of your 1099-R and will expect to see you report it. If it is not reported they will likely invite you to explain why.
However, slow down. You obviously rushed to file early without all of your documents (FIs have until 1/31/17 to put that information in the mail to you.) The amended return form 1040-X will not be available until mid-February. And, you CANNOT e-file an amended return, you
must PRINT and MAIL it --it usually takes the IRS 2-4 months to process an amended return.
Finally, you need to
WAIT until you find out if your return has been
REJECTED or ACCEPTED.
If it has been
rejected that you can
simply make the corrections required to fix the rejection AND at the same time add the information from the 1099-R, and re-submit your CORRECTED e-filed return.
If it has been
accepted you will have to
prepare and mail an amended return ---BUT
WAIT until you receive your refund before filing the amended return
.
When mailing a printed return it is always a good idea to go to the Post Office and mail it 'Certified' with 'Return Receipt'. That way you will have proof that they received it and when it was received.