Tax amendment and penalty

Hello,

I filed my tax return for 2019 in March 2020, in which I owe an amount. And I filed an amendment for the same return in April 2040, in which I get a refund. My amendment has not been processed yet. And, yesterday I got a letter from IRS notifying me of the interest and penalty. Should I wait for the amendment to be processed to get refund or should I pay the tax that is due now?