What Causes Pain In Shin And Foot While Walking?

Hi, I am experiencing pain when I walk at the left side of my shin and occasionaly it wil be accompanied with pain to the Right side of the ball of my foot. It only happens as soon as I start walking and stops when stop walking. I find I a unable to walk very far at all now due to the pain which is around level 7/8. This has been going on now for around 6/8 weeks