Mine was messed up from an auto accident and a couple of 5 hour gut surgeries where they pressed down on that area. I also have spina bifida, broken coccix, a couple of lumbar tears and other stuff up and down my entire spine. Can deal with it all but the sacroiliac is the worst. When that goes out it’s searing pain.
I always sit on a folding hip cushion, so my hips and tailbone sink lower into it than the rest of my rear. Tried every kind of cushion and this is the only kind that works. Got it on amazon years ago. I use it every time I’m out of the house. I also sit on an air cushion on my recliner and sleep on an air pump cushion.
The rest of the stuff, prayer, meditation, distraction through hobbies, minimal rx and otc if actually needed, help. I only go to the doctor for it if I can’t walk. They usually refer me to PT which I’ve had to do several times over the years. I’ve had to use a walker for awhile, then a cane most of my life, in between being fine without it for years.
I use heat packs for aches and cool for searing or burning. You can make your own packs by putting rice in a sock or a little sewn bag. For heat, microwave 15 seconds and only leave on skin for up to 1 1/2 minutes at most depending on your heat tolerance. You can put clothing or a towel in between to soak up some of the heat.
For cold packs put it in a zip lock bag in the freezer for 30 minutes with the same tolerance limits.
It’s been over 40 years for me but I’ve got it down. I know how to prevent injury and to recover. Not always successful with new injuries but that’s the best it’s going to get for me. Hope this helps.