When some thing like that happens to my pepper it is usually fungus infection

Yeah, there is a black fungus that attacks peppers, but it won't grow on an unblemished pepper. It needs some way to get in there before it takes hold.

Unfortunately, it doesn't take much to let it in. An insect bite can do it, or even just a sudden spell with too much water that makes the skin crack a little can do it.

Sounds to me like sunscald. The good thing about sunscald is that the rest of the pepper is usually perfectly edible. If you can just cut away the black area, sunscald is the most likely cause.

Here is a pic of the same type of damage although this is on one of my tomatoes

{{gwi:99768}}

It looks sort of like anthracnose.

Here is a link that might be useful: tomato problem solver