Pain in the back of the foot without swelling may be physiological pain, or it may be caused by lower extremity venous thrombosis, trauma, osteoarthritis, and gouty arthritis and other diseases. 1. Physiological pain: If walking or standing for a long time leads to the accumulation of lactic acid in the muscles of the back of the foot, causing physiological pain in the back of the foot, which can be relieved after resting. 2. Lower extremity venous thrombosis: Lower extremity venous thrombosis can cause blood reflux obstruction in the feet, resulting in local ischemia and hypoxia, causing pain and swelling in the back of the feet. 3. Trauma: If the back of the foot has a history of trauma such as sprains, smashes, etc., the damage to the soft tissues or bones may cause the symptoms of pain although the swelling is not obvious, and X-rays need to be taken for further diagnosis. 4. Osteoarthritis: Osteoarthritis with osteophytes can cause pain in the back of the foot, especially when the pain is aggravated by exertion, strenuous activities or exposure to cold. 5. Gouty arthritis: Gouty people have increased blood uric acid due to abnormal purine metabolism in the body. If you eat a lot of seafood and other foods that contain more purines, it can cause uric acid to rise, inducing gout and causing pain in the feet. There are many other reasons for the back of the foot pain without swelling, such as lumbar disc herniation, etc. If rest can not be relieved, or accompanied by other discomforts, it is recommended to consult a doctor in a timely manner, improve the relevant examination, and follow the doctor’s instructions for further treatment after a clear diagnosis.