Plantaris could be the real problem..
This is an amazing picture of a ruptured Achilles tendon. Interestingly the smaller tendon running alongside is still intact. This muscle is Plantaris which has historically been ignored when looking for probable causes of calf/heel pain. If you have "Achilles" pain but it's a bit higher and on the inside of your calf it may be this smaller muscle/tendon causing the problem.
Recent evidence indicates a graded loading rehabilitation programme to resolve this problem which our physiotherapists are always happy to provide!
Bath Physio 01225 683007
Physioimpulse Chartered Physiotherapists