Muscle cramps. This sudden, tight, intense lower leg pain is sometimes called a charley horse. Often caused by muscle fatigue, heat, or dehydration, muscle cramps are more common among older people, endurance athletes, or athletes who are not well conditioned. In most cases, you can ease muscle cramps by stopping whatever triggered them. If needed, gently stretch or massage your lower leg muscle. Applying heat to tight muscles or cold to tender muscles may ease some symptoms. Proper conditioning and stretching can help prevent problems in the future.