Pain/tightness around (possible) accessory bone after exercise

Just hoping to get a little clarification on what medical professional I'm best consulting and how to phrase my problem to them.

When I was 14 I rolled over onto the outside edge of my right foot - inversion sprain as I understand it.

However, the resulting pain (which lasted for weeks and made it very painful to walk) was medial. A prominent bony lump had appeared which is still there to this day, and which I now understand could possibly be an accessory bone that I either hadn't noticed until that point, or was made more prominent by the injury?

After that, the ankle became somewhat unstable and I would accidentally roll over on it (inversion) quite easily. But every time, the resulting pain afterwards would be medial.

Now (late twenties), whenever I do a lot of walking, or a low to moderate amount of running, it feels like the ligaments surrounding the bony lump have become very tight. It's painful to the touch but this can be partially relieved by self-massaging the area.

It would be great to get an idea what might be happening, and what a physiotherapist could potentially do for me, before I approach a private physio (as I wouldn't feel comfortable going NHS-route for something which isn't really causing me daily pain).

Many thanks in advance for any thoughts.