The causes of calf and ankle pain will vary significantly from person to person, but common causes include injuries and trauma, overuse of the ankle joint or calves, ruptured muscles, muscle strains, shin splints, and even nerve damage. Calf and ankle pain may occur simultaneously or independently; if the pain occurs simultaneously, the cause of the pain may be linked to the muscles, tendons, ligaments, or bones in that area, or the nerve that services that area of the body may be compressed or otherwise damaged, leading to painful sensations throughout the lower leg. A proper diagnosis is usually necessary, which means a doctor's visit may be in order.

Injuries resulting from some sort of trauma are the most common causes of calf and ankle pain. A bone fracture, for example, can cause mild to severe pain in the affected region; a fracture in the heel may cause pain throughout the foot as well as the lower leg. An injury on one leg can also cause pain in the other leg, as the uninjured leg must often bear more of the body's weight to compensate for the injured leg. If the calf and ankle pain occurs in the same leg, the pain in one area may be referred pain that results from an injury in the other area. Referred pain is a type of pain that occurs in another area of the body than the one that is directly injured.

Any of the nerves that service the lower legs can cause calf and ankle pain independently or simultaneously. The sciatic nerve, for example, starts in the lower back and runs all the way down to the feet. If this nerve gets compressed or otherwise damaged anywhere along its length, it may cause pain in any part of the legs, lower back, hips, or feet. Nerve pain is often a sharp pain, though it can also manifest itself as numbness, weakness, soreness, dull aches, and even a loss of motor control in certain areas of the lower body. If a person experiences severe neurological issues such as a loss of motor control, he or she should visit a doctor immediately.

Muscle strains and ruptures can also cause calf and ankle pain. A strain occurs when the tiny fibers that make up a muscle begin to tear due to abnormal use or sudden shock. A rupture occurs when the muscle separates entirely from itself or from tendons that connect it to bone. A rupture is considered a serious condition and will often require a surgery to fix.