I have a kidney infection i've been useing antibiotics its been 8 days and i still have pain is it getting worse?

Maybe yes: Depends on where your pain is, but i would worry if you still have symptoms despite treatment that you may have a resistant infection or it has gotten worse. Especially if the pain is in your back, I am concerned about a kidney infection (pyelonephritis) instead of bladder (cystitis). With fever, chills, or other symptoms, likely best to be rechecked.

See your physician.: Kidney infections are serious and require prompt treatment with the right antibiotic. Hopefully you have a urine culture result by now which will show the correct antibiotic. Flank pain is common even on proper therapy, but worsening pain & fever requires re-evaluation with physical exam & possibly imaging as your current regimen may be inadequate. See your physician as soon as you can.