Chronic sij pain. Becomes displaced often. 2 steroid inj with min brief relief (2wks) now pain seems even worse 8/10 on pain scale constantly. Surgery?

Probably not surgery. Sacroiliac joint pain occurs because the muscles where the spine and pelvis meet are involved in bending, twisting, and lifting. Pain from a sprain or strain may be helped with nonsteroidals or local injections. You may need physical therapy to strengthen and stretch your muscles so there's not so much strain on that joint. Surgery probably won't help your pain and may decrease function.
No surgery . Discuss with your physician about getting mri. The joint may also need to be cultured to be sure it's not infected. You need a clear diagnosis as to why it's so painful.