I'm not convinced it's early fert burn, just pointing out that could be part of the problem. Chile plant leaves are generally rather smooth, but you can see that leaf to the right (in the pic I linked to) is not smooth at all - I am calling that "puckering". The thing about early fert burn is that, most often, the puckering is exhibited across many leaves, and there are often no signs of anything else wrong (though not always.)
Sunburn often turns leaves (or parts of leaves more exposed to sun) white, and thins the walls of the leaves. The second pic down has a whitish look to the edges, unlike the pic above it, which is strongly yellow. Third pic down some leaves are smooth, some puckered, and some have yellow at the edges.
There's a graphic of some common deficiencies on this site:
http://tomatoheadquarters.com/tag/heirloom-tomatoes/#lightbox/4/
Scroll down to find it. Keep in mind that tomatoes and peppers are related, so their symptoms tend to be the same.