The ankle pain you are describing is possibly due to some trauma which could lead to a sprain or ligament injury. Mechanism of injury is important to know if there was any trauma. Also at your age ligament laxity is common which could cause instability of joint and gives feeling of 'popping out' and causing limited movement.
Next Steps
Kindly visit your nearest physiotherapist for detailed examination and correct diagnosis.
Health Tips
Use a good footwear which supports your ankle well. If possible use shoes which has laces so that you can tie is tight enough to support your ankle.