This article is from the Running FAQ, by Ozzie Gontang with numerous contributions by others.
1. Warm up before you stretch. This could be in the form of a slow jog as
you start your run. When I feel it necessary, I stop for a few minutes and
stretch during the early stages of a run.
2. Stretch after your run. This has proven the best solution for me.
Whenever I skip this part, I end up stiff the next day. The muscles are
nice and warm after a run and respond well to stretching. My flexibility
has improved as a result of this practice, too.
3. With regards to an injury, you've got to be tough and rest it in order
for it to heal. This might be a good time to concentrate on strength
training with weights.
The good news: since this seems to be your first injury, and your training
load is light, your tendinitis is probably due to the most simple cause -
leg length imbalance. Get someone to mark how far you can bend to each
side, if these are different heights then you might find a heel raiser
under the bad leg will both even out the side-bend _and_ speed up the
The bad news: achilles is notoriously slow to heal even with the correct
treatment. And the chances of recurrence are quite high. However the
condition you describe shouldn't prevent your training, as long as you
promote healing with stretching, massage (calf/inner thigh/groin), ice,