Thigh pain when leaning over the right leg to the left leg may be caused by herniated lumbar disc, muscle strain, muscle injury and so on. 1. Herniated lumbar disc: As the herniated lumbar disc presses on the nerves, the activity is affected, and the right leg will feel very hard and thigh pain when leaning over to the left leg, as well as numbness of the right leg and other symptoms. 2. Muscle strain: local muscle strain, in some stimulation will appear discomfort, the right leg to the left leg side to lean over the muscle will cause pain. 3. Muscle strain: It may be that the muscle has been strained at some time before, and the local tissues are swollen, which will cause pain when being pulled. This situation may also be caused by other reasons, such as hip arthritis, necrosis of the femoral head, etc. It is recommended that when the symptoms of the above pain continue to be unrelieved, you should consult a doctor in a timely manner, undergo the appropriate examination to determine the cause of the disease, and follow the doctor’s instructions to carry out targeted treatment in order to avoid delays in the condition.