What Is The Treatment For Severe Pain In The Middle Of The Spinal Cord?

I am a 54 year old female and i weigh roughly 270 pounds. a few years ago i fell in the bath tub and landed hard on my back. Ever since i have experianced pain in the middle of my spinal chord but two inches off to the left. It feels like a knife in being jabbed into my back. It is also causing my left shoulder disk hurt. My physical activity has been rendered greatly bacause of this ( hence the weight gain). What could the problem possibly be?