When I was 19 years old I broke my left fibula, a couple of inches above my ankle. I wore a cast for 6 weeks and it healed without any complications. I am now 58 and am experiencing pain at the fracture site. I'm physically active and in good health and normal weight for my height and age. Pain occurs often without warning from doing simple tasks.
It would be very uncommon for a patient to develop pain around a well healed fracture that many years out from injury. Especially, if there was no problems in the interval.
But, if the discomfort is signficantly bothering you, you might have the area evaluated by an orthopedic surgeon. It could be that you have finally developed some traumatic arthritis in the region (but again, that would be very uncommon this far out from injury). You could have developed a new problem in the area. Such as peroneal tendonitis or tenosynovitis. There is also some nerves in that region, which could manifest as tarsal tunnel syndrome. Who knows.