Hi It is good to assess the strength and Range of motion of ankle joint . There may be tightness in the tibialis ms .You need to consult a Physiotherapist for proper assessment.

The causes of pain. in the leg could be related to bone or muscle.  A proper diagnosis would ne needed to determine the exact cause. Of muscle, you would need to do stretches for tribal muscles for normal flexibility. Also, strengthening of these muscles are vital. Of you wish to run 10 km, it is preferable to do stretches and strengthening of lower body and core for good performance.

you seem to be getting something called a shin split.  These usually happen when you have under worked your quadriceps muscle.  The load and weight transfer happens on the shin then.  ensure you do good quad and calf strengthening exercises.  do short rings to build up endurance in them with frequent breaks. If pain still persists consult a physio for a hands on approach