Old scar from giving birth keeps tearing

Okay so I had my first baby almost 3 years ago. When I had her the midwife said I tore and she gave me 2 or 3 stitches. I healed and everything was all good. I got pregnant with my second baby when my first was a little Over a year old and during my second pregnancy I was having burning pain when I had sex and when I peed. I went to the dr and she took a look and asked if I had torn with my first and I said yes. She told me that it tore open a little and to use enough lube. I didn’t know it was possible to tear after so long!🤦🏻‍♀️ and see the thing is my second baby just turned one and sometimes when I have sex I can feel that scar tear open a tiny bit and then it burns when I pee. It’s feels uncomfortable.

Again it’s been almost 3 years since I had my first baby that I tore and when I had my second baby I didn’t tear at all! How can this be???? Anyone else have this issue? I think I need to go back to the doctor after this corona Virus calms down. 😢