Could be blossom end rot.Ive see it on a few peppers every year.It is not contagious so it will not infect other peppers. If you look at the tips of any peppers left on the plant there will be a small healed over hole instead of the usual tip. I suggest examining a few and cutting them open to see what you have.After a little trial and error you develop an eye for it. Did you use lime or gypsum ? Try some witches brew. Also uneven watering can cause this. If you can get most infected peppers off your plant it will produce more and not be wasting energy ripening unusable pods.
Good luck Im sure lots of members have seen this before.Very similar to what happens to tomatoes only on a pepper it becomes sealed inside the pepper. A good pepper should have a tip on it.

PepperDave-
Thanx, I'm not sure what witches brew is. i just fertizie with a general fertilizer once in awhile and water as needed. I'll take a few off tonight and see what they look like inside.