Unusually persistent pain, weather sensitive pain, skin color changes, swelling, abnormal sweating, and pain to what is usually a non-painful stimulus are all signs of  Reflex Sympathetic Dystrophy (RSD), also known as Chronic Regional Pain Syndrome (CRPS).  RSD/CRPS  almost always begins after an identifiable event such as a crush injury, torn ligament, or fracture.

Less severe forms of RSD also exist and in these cases sympathetic pain can occur even in the absence of injury.  RSD is difficult to diagnose and increasing awareness about RSD can help those with lingering pain after an injury to get treatment.

Venous Insufficiency can cause burning, itching, swollen painful legs.

While arteries carry blood away from the heart, veins carry it back. In order to make sure that the blood only flow in one direction, they have valves. If the valves do not work properly then blood may pool in the limbs (especially the legs). This is called reflux. It can cause swelling, burning, itching and skin color changes. Your legs may also feel heavy, tired, restless, or achy. You may feel pain while walking or shortly after stopping. This is called venous insufficiency.