SI belt, taping and PT may help.

My daughter had SI joint issues for years, and finally had PRP (platelet rich plasma), which involves drawing blood, spinning it and injecting the concentrated plasma into the joint. After 10 years of pain, PRP helped her in 24 hours. It doesn't work for everyone though. A physiatrist would evaluate you for PRP. Ours was in a mainstream top hospital rehab facility. But we paid $1k for it out of pocket.