Hello and Welcome to the Couch. I'm glad you found us and took the time to post.
I'm sorry to hear about your increased pain. This is not a normal response to an SIJ injection. Was this your first injection? The procedure is first utilized to DX (diagnosis) SIJD - the amount of immediate pain relief you experience will help confirm or deny the joint as a source of your pain.
They did the procedure with the aid of a fluoroscope - correct?? That should have assured that the injection went into the exact location.
I've had several SIJ injections. Initially there may be increased pain once the local anesthetic "wears off." They use a type of "caine" medication to numb the area before they inject anti-inflammatory cortisone agent. The steroid isn't effect immediately in reducing the pain - but over days- usually 2-5 - it should relieve the inflammation and any swelling in the area.
At 10 days the steroid should be effective. I'm sorry that's not true for you. Obviously something is wrong - either they missed the mark - or your pain is not associated with SIJD and it's referred pain - simply put that means originating in another location but felt elsewhere.
Here's an older post on SIJ injections. The information is still relevant. You may want to view this also.
http://www.medhelp.org/posts/Pain-Management/Pain-after-a-sacroiliac-joint-injection/show/1214829
I encourage you to return to the physician that preformed the procedure. It's not common to develop an infection following a SIJ injection but it does happen. I'd be sure that possibility was ruled out.
Have a long discussion with the practitioner that performed the procedure. Don't wait - insist on an appointment. Obviously he/she won't admit to making a mistake - if that's what happened. If the pain doesn't subside I'd get a second opinion. That second opinion should not be with a practitioner associated with the practitioner that did your injection - or the clinic or hospitals where he/she practices.
If you view the above link you'll see that this occurred when I had an SIJ injection but it was because the joint was misaligned or "out of place." Once it was realigned the pain decreased significantly.
SIJ can be difficult to treat. I've had SIJD for 20 years. I've been through most of the procedures and treatments to no avail. I've know other SIJD suffers that have had great results with certain treatments. We're all different as are the physicians that treat us. Skills, experience and education of practitioners vary. Finding a knowledgeable, experienced physician in SIJD can be difficult.
I wish you the best and hope you'll be active in the Group. It's always nice to "meet" someone with my condition - compare and learn.
I'll look forward to hearing from you again soon.
Take Care,
~Tuck