The pain may be due to muscle soreness. Consult any orthopaedician or physiotherapist for exact diagnosis. Take rest and avoid walking/jogging for few days till the pain subsides. Apply ice pack on painful area.
Next Steps
Always do a warm up and cool down whenever you go for walk or jog. Gradually increase the distance over a couple of weeks to get your body accustomed to it, instead of directly going for a 10 km distance. High carbohydrate diet prior to exercise will help to improve fitness.