What Causes Bruise On Lower Back Along With Numbness In Leg?

about a month ago, I noticed an unusual bruise on the left side of my lower back. I wasn't aware of how it came and didn't notice any obvious symptoms with the bruise. About two weeks ago, my left side from my waist down to my feet have felt numb with a tingling sensation. Hard to explain but my right leg doesn't feel like my left leg, sensation wise. I have no bladder or bowel problem and my coordination and strength appears to be equal. I am wondering if the loss of sensation relates to the bruise from 2 weeks earlier?