I recently had nerve block and cortisone injections for a prolapsed disc. The pain and tingling sensation are greatly reduced and I'm able to move better with greater flexibility. However, since then, I've been getting sharp, stabbing pains in the lower back on the side of the affected area. This is totally different from the pain I was feeling before the injections. It happens when I've been sitting for a while and I feel like I can't move until it goes away, which takes about 10 seconds. Has anyone experienced this?