If you have trouble finding enchilada sauce, I've used this recipe with success in the past: http://www.gimmesomeoven.com/red-enchilada-sauce/
Storage
After baking, enchiladas may be stored in the fridge. They are best eaten within 2 days.
To reheat- bake in a covered dish in the oven at 350°F for 20 minutes, or heat single portions in the microwave until steaming hot.
Freezing
Enchiladas freeze great, but they can get soggy while thawing. The best option is to roll (unbaked) and freeze in a metal baking dish. Transfer the frozen dish directly to the oven. Bake for 30-45 minutes (covered) and take the lid off during the last 5 minutes.