There are several ways to alleviate knee pain
I recently twisted my knee and the swelling that resulted limited my ability to do much exercise. Walking was not helpful as the swelling remained after each walk.
Bicycle riding was out because I couldn't bend my knee enough without pain on the upstroke of the circular motion of pedaling a bike.
I looked into knee injuries for runners and found that the knee is one of the most commonly injured body part. Some are minor injuries that disappear in a short time with a little rest and ice treatment. Others require a longer time period to let the runner get back on the road to their previous level of pain-free running.
It seems that there are several possible causes that contribute to knee problems.