Retirement tax questions

Thanks Kathryn. But this doesn't make common sense to me. Let me restate the question. I received a 2020 1099R with $4,600 in box 1, $4,300 in box 2 and $300 in box 5 and a "P" in box 7. This is an annuity from a defined benefit plan that I will receive until death. The contributions that I made go back to the 1980s. I didn't receive any excess contributions in 2019.  

If I have to amend my 2019 return, I 'll have to amend my 2020 return when I get when 2021 1099R, and for each year there after. File and amend for every year...doesn't make sense. 

Please advise. Thanks.