Thanks for your query
Look this first dose of steroid cannot cause low back pain
. Long term use of high dose systemic prednisone can cause low back pain due to osteoporosis
. I think in your case there is other cause of low back pain. So i advise you to go for atleast a digital x-ray of pelvis and lower lumbar vertebrae
to exclude causes of low back pain. This low back pain may also be due to para-spinal muscle spasm
. You may take analgesics with muscle relaxants for pain relief.