What Does Back Pain With Bruises In Hip Suggest?

I am 26 yrs and have been having lower back pain and trouble sleeping for days now. A red mark like a large bruise has appeared on my side that stretches across, above my hip area. It feels like a bruise to touch. The back pain is almost like period pain, but not and is across my back (Kidney area). At first I thought it was my kidneys, but I haven't seen any blood in my urine. So I am very concerned as to what is wrong with me!