Strange lower back discomfort?

A couple days ago i started feeling low back discomfort, it's hard to describe, it almost feels as if someone is pushing or stepping on my lower back even when I'm laying down flat I can feel some sort of strange pressure or sensation, I also started having diarrhea at the same time and trouble using the bath room, I went to the hospital and they did an x rays blood test urine test and a stool sample, they said Id only hear back if something was wrong, earlier last year I had a cervical epidural abscess caused from a stapgh infection that caused osteomyleitus. Will the blood test check for stapgh? What could this discomfort be from also I've been popping my back a lot lately and now I havnt been able to pop it so well! Any ideas?