Retirement tax questions

You need to get a IRS transcript of your account or ask them who the income is from.  Then contract the issuer why they sent the IRS a 1099R.    If it is legitimately yours they may have sent your 1099 copy to the wrong address.  If it’s for an account of yours you might be able to log in and download a pdf of the 1099R.   

Could be for many things.  Like an old 401K account that was liquidated when you left that employer.   Or did you roll over a 401K or IRA account to another account?   Or convert it to a ROTH IRA?   How old are you?   If you are over 72 you need to take a RMD from your accounts.  Maybe you forgot account an old account.