Numbness and pain on the lateral side of the right leg is due to the following two causes: 1. The most common cause of skin pain and numbness on the lateral side of the right leg is lateral femoral cutaneous neuritis. The most common cause of pain and numbness in the right lateral leg is lateral femoral dermatomal neuritis. When a lumbar disc herniation occurs, it will compress the nerve root, which is responsible for the skin sensation and movement of the lower extremity, so the nerve root will also cause numbness and pain in the lateral right leg after being stimulated.