I Noticed A Couple Months Ago That I Had A

I noticed a couple months ago that I had a small (dime sized) blue bruise at the end of my spine. It doesn't hurt when touched. Along with this, i have been having serious stabbing pains in my left lower back that shoot down my leg, sometimes. Now, I have it on my right side. I have been doing recommend exercises for the sciatica nerve, but the pain is not subsiding. When it does happen, it stops me in my tracks.