If you are truly experiencing Achilles pain then the best advice given is to stay off of it and rest. If it is injured and you continue to stress it you are only going to cause further injury which is going to lead to an extended period of time away from cycling. I injured my Achilles and thought I could bear the pain and ran anyways and I ended up having to take a full 2 weeks off with no running or biking. For someone who is very active that is VERY hard to do.

Listen to your body and if you are experiencing pain then give it some rest.