Why is the screen freezing and touching itself?

This sounds like a sign of water damage

Lots of misinput could also be caused by dust between your screen protector and the screen.

Try cleaning your screen and replacing the screen protector if applicable.

Screen freezing can be caused by RAM issues, overheating, low temperature, memory issues, and several other factors. If you are 100% sure that the screen freezing is not a software issue, and the misinput is still occurring, you may want to consider a hardware replacement.

Fortunately, iFixit does offer a Samsung Galaxy A03 Screen Replacement Guide. I hope this response is useful and helps you with your issue.