Dark shadow on lower right screen of iPhone 11

I recently got a dark black shadow on my iPhone 11 lower right of the screen. I did not drop the phone not once and the spot appeared suddenly. But it’s been happening more recently after I updated to the IOS 14.3... and phone is also getting heat frequently when charging and using. Is this something Apple will repair free of charge? Because my 1 year warranty was expired now.

I had an iPhone 6s for 4 years and still using but never came across this problem before.