My doctor doesn't find a spine problem; what else could it be?

About 5 years ago 2 events happened:
1) I picked up a cooler and felt something rub together or shift in my lower right back/buttocks. The pain went away after being in bed a few days, but I had an odd sort of vibration feeling in the front of pelvic area.
2) 3 months later I came down hard on one side of my body while playing frisbee. This created a bad pain in lower right back and back of thigh. The leg pain went away for the most part, but the back pain and hip cramping, groin pull pain,nerve pain never did. Over the following 3 years I' had:
-2 lumbar MRIs- degenerative disc disease is only thing of note
-EMG- negative
- 2 epidurals with little to no effect.
-2 failed PT attempts
-2 otho Dr. and a neurosurgeon visits. They don't know what's wrong

3 months ago, It became really bad and then I reached down to my right to pick up a pick of paper on the floor, and bam, that shifting feeling again...and now, it never got better, especially the back of the leg pain while walking and groin pull pain. I decided to go to a new pain management Dr. who thinks it SI joint. 2 steroid shots later and it's a little better, but I still can't walk more than 10 steps without pain in my leg and back. I'm scheduled for lidocaine injection in the facet joint next week to rule that out, but I had that a couple years ago, and it didn't work. Also have another EMG scheduled next month.

Things that help with pain: Generally sitting forward somehow stretches the nerve compression, so that's tolerable, especially bending forward. That's about it.

I cannot twist to the right at all, without major back cramping/pain feeling, into my hip and back of thigh.

I'm crying all the time and fell helpless cause I cannot get an accurate diagnosis, and the tests are not showing things that would cause this. Also, I feel like there might be 2 things going on at once. It doesn't seem like piriformis, given sitting is ok, especially leaning on my left side.

I apologize for this long post, but man I'm struggling with this. My daughters wedding is in 2 months.