Footage of you squatting would be very helpful here, just in case we can spot something that your coaches aren’t (no disrespect to them, obviously).

Mobility-wise, seek the high medial hamstring / adductor area. Episode 82 has a few ideas for getting after this stuff, but it can be way sensitive. Don’t be afraid to downgrade to a softer ball, or throw a folded towel over the Olympic bar first (regarding the later mobilizations in the video).