I have sacroiliitis which I understand is inflammation of the sacroiliac joint. I have been receiving physical therapy. I have been receiving physical therapy, about 18 sessions over three months. There is some slow reduction of the pain I experience.

See details. Physical therapy is obviously not the answer in your case. See a rheumatologist and have the issue reevaluated. There are many other treatment options available depending on the underlying cause.
Sacroiliitis . Sacroiliitis is commonly confused with back problems. The pain is located in butt in the pocket area of pants. Patients tend to not want to sit on the painful side. It is usually tender to push over the area. Sacroiliitis may be treated with physical therapy, steroid injections, radiofrequency ablation (burning) and endoscopic rhizotomy (nerve cutting) and surgery. Steroid injections often provide short term relief (months) and the addition of physical therapy may be beneficial. Nerve burning and endoscopic rhizotomy may provide significant but usually temporary pain relief due to the diffuse wide spread innervation of the sacroiliac joint from both front and back of the joint. New surgical techniques and devices have recently been or are in the process of being released (fda approved) which gives hope for longterm treatment in the future. Please see my health guides on endoscopic rhizotomy. Good luck!