Possible causes of right lateral thigh pain include muscle strain, lumbar disc herniation, and pyriformis syndrome. 1. Muscle strain: In the course of exercise, the right thigh and calf muscles may be strained due to over-exercise or improper exercise, resulting in a bout of pain on the outside of the thigh and calf, accompanied by swelling symptoms. 2. Lumbar disc herniation: If the patient suffers from lumbar disc herniation, when the nerve root on the right side of the thigh is compressed, it can lead to the symptom of radiating pain on the right side of the thigh and the outer side of the calf, and the phenomenon occurs. 3. Piriformis syndrome: Piriformis syndrome is mainly caused by the sciatic nerve being compressed in the region of the piriformis muscle. Patients mainly manifested as sciatica, in addition to the phenomenon can also be manifested as buttock pain and lower extremity radiating pain. A burst of pain in the right lateral thigh may also have other causes, it is recommended to go to the hospital in time to improve the examination, clear the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.