My horse is 16 pretty solid...gets hocks injected every year but otherwise very sound. He got injected two Fridays ago, and Saturday we went to a race and he crow hopped right after he switched leads going into the second, around to the third and home. He has done this before a year ago and we injected hocks, still he did it...took him to get a second opinon they re injected his R hock and he still did it. I changed saddle pads and didnt have an issue again.

This year I injected him as he wasn't finishing his turns, gave him 7 days off and when I went to a race...he crow hopped...Now here we are again with a call to the vet.

I tried two differnet saddle pads as well as a different saddle. He is not back sore or cinchy. Nor does he have hot puffy hocks.

Have you had his SI checked? My mare never bucked but she would crossfire bad and climb coming off the barrels. I'd injected her hocks, which usually fixed the crossfire issue, but she needed her SI injected. It made a world of difference in her performance and attitude. 

Is her canter more like a "bunny hop"?  If so, I would look into PSSM

This. . . I've gotten so I can tell a PSSM horse just be how it moves, most do the stiff-legged bunny hop.  And there are plenty of them out there.

Both si and hocks reinjected at day 12 since injections and still crow hopping

What I have learned about the SI is if its been hurting for a long period of time it will potentially take months to resolve. It is not an immediate issue resolved type injection, because it causes all the muscles in their back and hip to work incorrectly. So if it was your horse's SI causing the issue it may be awhile. I'm on week 2 since mine had it done and while she still rides the same, refusing forard motion, she is showing less sign of soreness during palpation on the area as of just yesterday. You might just be in for a longer wait for results. Mine has been sore in her SI for 3 years and I was told it would be probably 6 months to fully resolve and may need a second injection. And she's mostly been a sitting pasture pet for those 3 years not aggravating it much at all regularly. I imagine had she been in regualr work things would be worse. 

So I would just give it more time. 

I had one who did this and turned out his heels were sore.  Changed up his shoeing & quit.