What causes lancing pain in the knee medial? It hurts so much it is almost unable could it be a tear or a displacement of the meniscus? Please help

Either. It could be either of the 2 and some more possibilities, like early arthritis, loose body, or referred pain from a back/hip lesion. I think you need to go to your orthopod and get it investigated/treated. In the meantime, take some nsaids, rest your knee and use a cane or crutches if you have them and know how to use them, to minimize taking through that side. Good luck.