You might want to get some physical therapy and/or massage. I've had SI problems for many, many years, and it seldom keeps me awake. It does bother me - but I'm a 3/4 side sleeper. No way can I sleep on my back. In fact, I had a HIDA scan last month and laying on my back for 1.5 hours almost killed me, LOL.
I did buy a SI pad that I can lay on if things are really bothering me and it will realign my pelvis. I've also learned over the years that it is very very important to maintain abdominal strength and hamstring strength to support my SI. I do yoga once a week and make sure I get some good twisting stretches in because I'm pretty sure that most of my pain is due to my pelvis being misaligned. Last year I tried a cortisone shot in the SI and then had an MRI with contrast to see if there was any active inflammation. The shot didn't help and the MRI showed nothing except arthritic changes in the joints, both sides.
My rheumy would like me to try stronger meds to stop further changes but my GI thinks my CD isn't bad enough. I'm on the fence.