The swelling and pain in the back of the foot is mainly considered in the following three aspects: 1. Infection. Bacteria through the skin into the soft tissue bacterial infection, will lead to local inflammation, will be manifested as red, swollen, hot, painful, some patients will appear generalized fever, walking activities are affected, generally need to go through anti-inflammatory treatment to recover, and even septic situation, need to be incised and drained. 2, gout. Common in patients with hyperuricemia after eating meat or seafood, because of the amount of purine contained in such food, there is a sharp increase in blood uric acid, the formation of crystals deposited in the soft tissue of the foot, will lead to redness, swelling, pain, pain, it is necessary to control the diet, and then promote uric acid excretion to recover. 3, deep vein thrombosis of the lower limbs. Venous thrombosis leads to the restriction of venous reflux, and the distal blood supply still has not improved significantly, which will lead to local soft tissue edema and pain, and can be clarified by performing venous ultrasound of lower limbs.