Not Cathe here.
Here are a few little things that, in the long run, might help.
It is my understanding that the higher the heels, the greater the likelihood of Achilles problems, since the tendons shorten. Imagine the effect of each inch of heel height. If you wear heels, trying switching as much as possible to flatter shoes.
When you are in a hot shower or bath, and your heel is warm, trying stretching it some. The heat will help the flexibility. When you get out of the tub or shower, do some stretches you would normally do for Achilles, again, hopefully the heat will permit greater flexibility.
Some yoga books I read in the past talk about stretching in two stages. Apparently our muscles have an instinctive tendency to resist a stretch in order to protect a muscle from injury, e.g. if you stretch quickly, the muscle tenses up to resist in order to protect itself. So the yoga books said to go into a stretch gently and hold the stretch for about 10 seconds. By the end of that, the muscle should loosen a bit, then try to deepen the stretch a bit further and hold that for another 10 seconds. If this feels uncomfortable or hurts, then go slower. Most likely if you browse in some yoga books in a bookstore for 10 or 20 minutes, you will find this discussed in greater detail.
On several Cathe DVDs that I have, she does calf lifts. You stand on the balls of your feet on a step with your heels hanging over the edge and do regular calf lifts. You get more stretch since your heel is dipping below level. If you don't have a step, put two dumbbells on the floor (be sure to use the kind that don't roll), and step on those, and go up and down. When you do this, hold onto to something for balance. Flexible Achilles don't do you much good if you smash your head on a table after losing your balance. I put the dumbbells on the floor behind a chair and then hold onto the back of the chairlightly, just for balance. My kickboxing teacher has us do these in three positions, feet facing forward, toes pointing outwards, and toes pointing inward, to reach different areas of the calf muscle. Also, if your Achilles are tight, be very very careful to control how low you go. Going down, you have momentum and your body weight urging you down, so be sure not to lose your focus or you might tear something on the downward movement (mega-Ouch!!). Doing them slowly will help with this. A modification of this is just to put a length of two by four on the floor by your bathroom sink. Stand on it while you brush your teeth just letting your heels hang down.
Good luck.