this same thing happened to me - left ankle ball, burning sensation, at first it felt like a rock in my boots or like my canting screw was cutting through the liner and scrapping my ankle. almost couldn't walk at the end of the day. tore the boot apart and found nothing wrong, not to mention they are heat molded and dialed to my feet. went to see the doc after 3 weeks of skiing pain and found out i have tendonitis. there is a tendon that runs right over your ankle ball and it has to go through a sheath. if the tendon gets overworked or with age - it becomes inflamed,can't slide smoothly through the sheath, and causes pain like you are describing. might not be tendonitis if you are real young, but it is a possability. if you do have tendonitis - pm me and let me know what your doc says or if you have any questions. good luck with it.