One reason many people experience achillies and shin pain is that they land on their toes while running. Their ankles are plantar flexed. When you land in such a way you tend to land with the center of mass behind the toes or point of impact. This can lead to achillies pain and also slow you down. A plantar flexed ankle leads to less knee flexion.
Ankling is a great drill for part of your warm up or on technique days. Simply stated, it's running and landing on dorsiflexed ankle, cueing "curl the toes towards your shin" before and after contact. Getting the ankle dorsiflexed as fast as possible after ground contact and knee flexed will speed up hip flexion.
So, dorsiflexed ankles will not only speed up your sprint times, but will keep shin pain and achillies pain at bay.