I am a healthy 53 year old male. I jog, play golf (walk) , lift weights, etc. No skeletal abnormalities that I am aware of. I too am having a deep pain in my left side kidney at night mainly when I lay on my back. A sharp, dull stabbing like pain. No problems during the day when upright. No urinary issues either. Sometimes, hurts when move to my right side. This has now been ongoing for about 2-3 weeks. A sharp, dull stabbing like pain. Have never had this pain before. What could be the problem? Urinary infection or could this even be kidney cancer??