If you are sure you can eliminate pests (have you checked for mites?), and your watering and temps are not too blame, then the culprit could be calcium deficiency. Applying calcium nitrate should fix that quickly.

What are you using for fertilizer?

Looked closely at leaves and saw nothing. Fertilized with espoma garden tone. Also added dolomite which contains calcium magnesium. It might be some kind of disease or bug that I can't wee because a little bit of narrow leaf is affecting plant right next to it.

If your plants grow in a potting mix, dry organic fertilizers are not the best option. Real soil contains organisms that break down organic fertilizers (all those ground feathers, bones, etc.) and make them available to the plants after a while. Potting mixes are usually sterile, so organic fertilizers just sit there and are not fast/effective. I would switch to some liquid fert and see if that makes a difference.

I have been using org fert for many moons. While I agree not as effective as inorganic they do provide nutrition as the plants stand to attention after eating. Anyway I have used alfalfa tea. The next pant over is a cherry pepper that showing some narrow leaf growth but the next cherry is fine. So I think something is attacking but no idea what.

Broad mites. They are microscopic and cannot be seen with naked eyes. As someone who has struggled with them for a couple of years now, my sincere advice is to destroy the plants and trash the potting mix. If there are adjacent unaffected plants, move them away with as little of the common soil/mix as possible. And keep an eye on them, quarantine them.

Pest Of The Month: Broad Mite - Growing Produce

Thanks I will do that