I was playing tennis and i heard a loud pop in my knee. since then it's been hurting so bad, i iced it right away but it still hurts when i try walkin?

Ice and elevate: Normally when one hears a " pop " during an athletic injury a tendon, ligament or meniscus has been damaged. The standard of care is RICE, rest, ice, compression and elevation. It would be normal to hurt for a period of time, days to weeks. The key is if it improves or worsens. After a week if there is no improvement you need to be seen. If pain or function worsens you need to consult. Take care.