I have such a question?. I gave birth 3 months ago, the PA was 1 time,…

I have such a question?. I gave birth 3 months ago, the PA was 1 time, after giving birth I had postpartum uterine involution and it's a bit painful and unpleasant to do PA. Now I think, can I really do it? What if the uterus just goes down from this ? I am doing it, I am doing pelvic floor exercises. How long does the involution last? And what could be the final stages? Does it affect future births and pregnancies.