If you have a sore achilles after exercise then you need to try squeezing it as hard as you can take for about 15 minutes up and down, it will be really painful to start with but after a while it goes a bit numb and is bearable.
I had sore achilles after playing football for about a year. I did this just ONCE and it has fixed the pain and it hasn't come back. Apparently the squeezing realigns the fibres in the tendon, either way, I was amazed at how this worked for me. It is painful to do though so don't be a wimp about it.
Found the link!