I landed straight on my knee and it doesn't hurt when i walk.a lot of pain when i touch it and very bruised and swollen, should i get it checked out?

Need more info : Look at the "Ottowa knee rules" at http://www.emottawa.ca/assets/documents/research/cdr_knee_card.pdf to see if an x-ray is needed. There could always be injury to inside of knee, but you really need an exam for that. It's frankly easier to do that exam a week or so after injury; it hurts the patient too much to have their knee twisted and pulled right after injury.