I really feel you on this, that kind of sudden change sounds so uncomfortable and scary, especially when you were not expecting it at all. Breast tissue during pregnancy can go through these sudden surges due to hormonal fluctuations, so what you experienced might be related to that, but because it was so painful and came with new stretch marks, I think it is worth bringing up with your gynae or PD at your next visit just to be safe. It is always better to get a professional to take a proper look rather than wonder, and your gynae will be able to tell you if it is something to monitor going forward.