The pain on the outside of the right foot is considered to be caused by peroneal tendonitis, ankle sprain, gout, bone fracture, lumbar disc herniation, and so on. 1. Peroneus longus shortus tendonitis: due to strenuous exercise or walking too much caused by peroneus longus shortus muscle strain, tendon aseptic inflammation, mainly for the lateral calf, lateral foot pain, pronounced inversion pain. 2. Ankle sprain: the ligaments and joint capsule around the ankle joint are damaged due to walking or sports, and the joint pain is obvious and the activity is limited. 3. Gout: acute pain, red and swollen joints, elevated uric acid in laboratory tests. 4. Fracture: if the pain on the outside of the foot is obvious after trauma, localized bruising, there may be a fracture, which needs to be clarified by radiographs. 5. Lumbar disc herniation: a herniated disc compressing the nerves can radiate to the pain in the lower limbs. Right foot lateral pain need to go to the hospital orthopedics into the examination, clear cause for further treatment.