Hello and welcome to HCM
At your age this problem may be due to Gout
i.e raised uric acid level or due to local tissue inflammation. Get your uric acid level check and consult your doctor.
Till than try with hot fermentation, local application of diclo
gel at the site, Wear crepe bandage and do the regular exercise of ankle as advised by your physiotherapist.
If you have a history of Rheumatoid Arthritis
than you have to rule out this but usually it does't occur at your age.
Hope this will help you.