Sorry the IRS has limited staff due to Covid-19. They just started opening the mail in June that's been stacking up. Back in March the IRS closed their processing centers and stopped processing mailed tax returns. An IRS spokesperson recently said that they have about 11 million pieces of unopened mail. So you have to keep waiting.
See this IRS page for the latest information
The IRS has not processed any paper filed tax returns for months due to the pandemic. They have only just recently started to process those tax returns on an as received basis.
Go to this IRS website for information - https://www.irs.gov/newsroom/irs-operations-during-covid-19-mission-critical-functions-continue
We’re experiencing delays in processing paper tax returns due to limited staffing. If you already filed a paper return, we will process it in the order we received it.
Do not file a second tax return or contact the IRS about the status of your return.
For the Stimulus Check.
If they didn't get your 2019 return early enough they will use your 2018 return to calculate it. See this chart on how to calculate it.
You will receive any additional credit to which you were entitled when you file your 2020 taxes. See question #30 here