Back pain at 30 weeks ideas?

Nina • 26, Married, Mother to 4 daughters!

I'm having some extreme but dull back pain. It starts at the kidneys and goes up to my shoulder blades. It's getting painful to breath. I went to my PCP because I thought kidney infection. She said there was no trace of bacteria or blood in my urine. She offered a Flexeril muscle relaxer which I declined. She had me call my OB and I'm waiting for her to call back. I don't think I pulled anything and nothing is going numb. Any ideas?