Back/kidney pain normal (close to egg retrieval)

Hi all. I am at a very high risk of OHSS (I have very severe PCOS, over 40 follicles, my estrogen is very high and practically doubled last night). I will be doing a Lupron trigger and have already been told I will be doing freeze all. I have had bloating and discomfort (my left ovary was bigger than my uterus in last ultrasound), but today has been unbearable. My back is killing me, and when I pee, I have a wave of pain through my back/kidney area. The bloating is also worse than it has been. Has anyone else had this issue before?