When playing golf my ankle becomes painful.
When playing golf, my right ankle becomes painful and swells up.
Swelling of both ankles is always a cause for concern to doctors, as it can be a symptom of heart failure, which also causes shortness of breath on exercise and on lying flat. This seems highly unlikely in your case, since it’s only affecting one side and is clearly linked to exercise and pain in the same ankle. Statistically, you’re highly likely to have some osteoarthritis (often called ‘wear and tear’ arthritis). High impact exercise like rugby, football and skiing, as well as squash, can result in damage to a joint, increasing your risk of osteoarthritis in later life. An ankle support and anti-inflammatory tablets such as ibuprofen or diclofenac, taken before you exercise may well help the swelling; so will putting your ankle up, ideally above the level of your heart.