Buggered Achilles Bit

After yesterdays little 3 miler i felt a little twinge in my right Achilles but just put it down to the normal soreness you get when getting back into running. I could still feell it when in bed in the early hours of the morning enough to wake me up. So i went for a very gentle 3 miler this morning. As i set off it was sore but then the pain went away but when i finished it started to really hurt.Here are some incredibly in depth and scientific diagrams any medical university would be proud of to explain it a little better.