After you file

Yes, but you likely will receive it in 2021 when you do your 2020 tax return.  Amended returns have to be filed by mail and the .  IRS right now is not processing mailed returns. In a normal year, it can take the IRS up to 16 weeks to process an amended return, this year it will likely take much longer, even until after stimulus checks are being issued.  You can. however, take one next year when you file.