Hi Tony,
I got botox and had the same issue as you except for me it was an awful pressure only when standing up after botox. Prior to the botox my pressure would go away when I would run. Somehow the long strides from running relaxed the pressure. I then had botox and the pressure is relentless. I went to the CRS two days ago and he said that it was weird for me to have this pain after the botox. He pushed on my Levator muscles and I launched off the table. It sounds like you have something similar. If it is levator ani syndrome (LAS) another intervention will only make it worse. I would recommend that you get evaluated for this prior to your LIS so that you dont do another procedure which will yield little benefit and possible harm if you dont need it. I am currently scheduled for physical therapy for the LAS.
LAS typically presents in a patient who has undergone multiple interventions without any improvement. The diagnosis can be missed quite easily.
Whether the botox led to my levator muscles to become strained or not, I am going to try the physical therapy. Maybe all the interventions led to this or maybe the interventions uncovered the root of all evil. Ill let you know.

Hello please say you got better

Tony - what happened? Are you ok now?