Knee pain from running can be located in front, on the outside or back of the knee. The knee is anatomically a complicated joint, so pain affecting it can be because of a number of reasons. These range from overuse and actual injuries, which can be treated, to benign growths, which must be removed. Consult with your physician if you are experiencing knee pain from running.
Runner's knee, pain that affects the front of the knee, can be because of overuse, injury, dislocation or misalignment of the kneecap or flat feet. Problems in other areas of the body, such as the hip, back, or thigh muscles, can also cause pain in the knee. Overuse can cause iliotibial band syndrome, which affects tissue on the outside of the knee that helps stabilize the knee. Baker's cyst, a benign growth, causes swelling and pain behind the knee, at the point where the upper leg meets the lower leg. This growth must be surgically removed. Rest, proper stretching, orthotics for flat feet and knee and thigh exercises may alleviate runner's knee and iliotibial band syndrome.
Note – This information has been taken from different internet sources.