Try this stretch:
Calf muscles. Stand up, facing a wall, about 2 feet away from it. Put your right leg in front and bend it, but keep your back leg straight. Your left foot should be flat on the floor. Then, push your hands against the wall until you feel a good stretch in the back of your left leg. Then, repeat the stretch with the other leg.
Just remember: Listen to your body and don’t stretch your muscles too far.