Painful Latch

Am

My left side has always been my slacker side, so when my daughter was 12mo I just stopped feeding her from the left. She never latched on it for long and she always kind of fussed about it so I just gave it up once she was well established on solids.

I’ve just had my second baby and I’m still nursing my toddler. When I try to latch the newborn on the left, it is excruciatingly painful. No issues on the right though. I wondered if it was a position issue, so I tried having my toddler latch on the left since I know she knows how to latch correctly, and it was the same excruciating pain. It doesn’t feel like that new nursing soreness, it feels like someone is rubbing a grinding stone against my nipple.

They’re both getting a nice deep latch so I don’t understand why this would happen. Has anyone else had this experience? I’m going to make an appointment with an IBCLC but until we can have a consult I just wanted to see what other mamas might think.