An achy knee is often caused by tightness or weakness in the muscles around the knee. These knee stretches and exercises should help relieve the knee pain.
The first exercise to help relieve an achy knee is a quad set. This will not only help strengthen the quad muscle, but it will also help loosen up the knee joint.
Next is a heel slide. This is a great way to get some bending or flexion in the knee. Using a strap can also help get an extra stretch.
The last three stretches are with a strap for some of the muscles that cross the knee joint. A hamstring stretch, IT band (or tensor fasciae lattae) stretch, and a quad stretch should help get rid of some of the achy pain around the knee.