Right leg swelling and pain may be related to strenuous exercise, varicose veins of the lower limbs, rheumatoid arthritis and so on. 1. Strenuous exercise: when the patient does not exercise for a long time, a lot of lactic acid will accumulate in the right leg muscle after strenuous exercise, which will lead to swelling and pain in the patient’s right leg. 2. Varicose veins of the lower limbs: when patients with varicose veins of the right leg are active, the blood in the varicose veins will be stagnant and leak out to the tissues, which will lead to the swelling of the leg tissues and cause the patients to feel swelling and pain in the right leg. 3. Rheumatoid arthritis: rheumatoid arthritis will cause local inflammatory reaction, when arthritis attack, a large number of inflammatory cells and inflammatory factors in the local joints will lead to aggravation of local inflammatory reaction and cause swelling of local soft tissues, which will lead to swelling and pain in the right leg. When patients experience swelling and pain in the right leg, they should seek medical treatment promptly. Treatment is carried out under the guidance of professional doctors.