You might have to get the MRI, I avoided getting one until I woke up one morning and could not use my left
leg. I had been having lower back/tail bone pain on
and off for months and they could not figure it out. The MRI revealed that 30% of my disc had broken out of my spine and apparently was floating in the spinal column until if finally just lodged itself against a nerve... and there went my leg, my foot was numb, I could not use it to walk at all. It required surgery.