I cannot "lock" my ankle anymore when I shoot a soccer ball?

I sprained my ankle about 2 months ago. Moderate lateral ankle sprain not too serious. It was supposed to heal in a 1-2 months. It's been 4 months and i cannon "lock" my ankle when i shoot a soccer ball. i can dribble, pass, and lob fine but i still cannot shoot the ball. when i do my ankle does not lock and it hurts to shoot. how much longer should i wait and/or what should i do?