How can i get rid of this pain?

okay so when i was walking home from school today, my knees really hurt like right under the squishy part under your knee. right where your shin starts. then i got home and i just put a little ice on them. so i went to practice, and i barely jogged my knees were just killing me. i mean killing. i couldnt run, and when i got home, it really hurt going up and down the stairs. whats wronge and how can i get rid of these pains? any excercises i could do? my right one hurts if i put pressure on it