don't know your age but if you're over 40 it's probably your body letting you know you're not a young man anymore.
ice and ibuprofen are necessary. if you have any kind of sharp pain, get into your doctor pretty darn soon. cartilage tears, in my limited personal experience, come with a sharp pain.
because of all the excess weight i carried, my knees took a horrible beating. losing a ton of weight (178 lbs. so far) has helped immeasurably. don't know you at all, and forgive me if this doesn't apply, but perhaps your weight needs to be dealt with honestly.