question: Hello doctor, I am 30 years old. I have been feeling pain in my left knee when I sit on the ground. When I get up it takes two minutes for the left knee to get normal and function without pain. I got a massage, but that did not work. Instead, my back started hurting slightly after that. Please advise whether it is calcium deficiency or any other cause. At normal times, it does not hurt much. My height is 6'1" and weight is 96 kg.