If you feel a pain along the front of the lower leg, it usually means you have a shin splint.
Shin splints are caused by an imbalance between muscles that raise the foot and ones that lower the foot. Try these tips to avoid shin splints.
When walking, try to take normal steps rather than over-striding. Proper footwear is key, so make sure you have a flexible shoe, running shoes work well. Before beginning the walk, do some toe raises and stretch your shins.