Hi Dawnie, Many of these posters within the last 3 years are probably suffering from tendonitis of the peroneus longus tendon, a tendon between your pinky toe and your heel, closer to the heel.
I am unlucky enough to have injured it as well.
It usually happens when you wear narrow shoes or uncomfortable shoes putting pressure on that tendon and moving it in an awkward position. It also happens during vigorous sports. I think I hurt myself during some competitive badminton. Happened yesterday and continually got worse.
It can also happen if you step wrong on to the side of your foot also injuring your ankle. Tendon pain usually ends up extending to pain of all the nerves in a line with that tendon. A tendon near my knee is starting to hurt as well.
I'm not a doctor but, if it is really bad you should see a doctor. But unless its serious the only things you can really do is prevent inflammation with ice and sports injury rubs. Then to accelerate healing, perform cold and hot baths of the affected area. Usually as hot water as you can stand and ice with water is the what the two buckets should consist of.
Put your foot in the cold bucket first if inflammed, then alternate ever 2-3 minutes. Ending with hot water if swelling has reduced and ending with cold if you still see any signs of swelling. This and general rest, ice, compression, elevation for most injuries can help. You can look up more on the internet.