If you have problems with chronic pain in your back, legs, or feet and your doctor can't pinpoint the cause, you should consider going to a podiatrist. You might have one leg that's shorter than the other. This is a fairly common condition. Many people have legs of different lengths, but the difference is usually small enough that it causes no problems. If there is too much difference, it throws your entire body out of alignment and leads to pain in various parts of your body.
If you play a lot of sports, such as basketball that requires jumping, you are at risk of getting a sprained ankle. Sprains happen when you land on the side of your foot after you jump. This causes your ankle to twist. The twisting motion damages ligaments and possibly the tendons and bones in your ankle. That's why ankle exercises are so important when you are an athlete. Strong ankles are more stable and less prone to sprains.