What's causing my kidney pain no infection but there's a stone in the center if the kidney tha drs said would not cause pain?

Hard to say... But they are correct that the presence of a stone in the kidney does not cause pain. Pain is caused by the a stone slipping out of the kidney and and into the ureter. Lower back pain is common, and usually caused by muscle sprains, either acute or chronic. See your physician for an exam and diagnosis.