Hello doctor. Actually doctor I don't know what is the problem with my both knees when I bend it something like bone is making a mountain when I bend it, it hurts means I think the bones are out of shape because I lift some heavy things also due to that I have pain in my lower back as well. But I don't know what is wrong with my knees. I hurts when I bend it. Like a bone is coming outside when I bend it. Please let me know what it is. And is it a small problem or a big one because I am so scared. It only hurts when I bend my knees because that bone comes out even when I sit cross leg then it also pain. Please help me to get rid of this.