Hello, where you are having pain whether it's on bony surface or over muscle? If on bony surface did you get any trauma or injury or hit by anything over it? If no or if you have pain over muscle, it could be due to strain due to excessive walking running, over rough surface or irregular surface, then no need to worry, Rest your legs to feel better. Ice helps. So can anti-inflammatory meds such as aspirin, ibuprofen, and naproxen, if your doctor says these are safe for you. You can buy them over the counter. You might want to see a orthopedician if the pain stays or any trauma or injury is present . Try not to do anything that makes your leg hurt more. Once it feels a little better, do some stretches. The next time out, wear comfortable, supportive shoes. And don't run on hard surfaces if possible.