This has happened to MILLIONS of Americans who filed in March, just as the IRS sent its employees home! Now it is overwhelmed catching up after getting stimulus payments out — adn those are behind too.
If you are owed a refund, they are paying interest at 5% back to April 15th for the second quarter, and at a rate of 3% for the third quarter. And the interest check might come separately from the refund check. Be patient.