The condition is called "Blossom Drop" (lots of info available on it if you search that term) and can affect any fruiting vegetable. Can be caused by excess nitrogen fertilizers, over-watering (in peppers), high winds, but the most common cause is temperature and humidity extremes. Fruiting plants will only set fruit within a certain range of temps. Outside that range the pollen is inactive, the bloom can pollinate itself, and the bloom dies and falls off.

Would need a great deal more info about your growing conditions to be more specific, but the damage on the leaf in the pic sure looks like excess nitrogen burn to me. Pepper plants are not tolerant of high nitrogen levels.

Dave

Agree with Dave that N excess appears to be the problem but if your garden is near a road that received salt this winter the signs may look the same. You could perform a Total Soluble Salts test to check soil salt level. You might even do the same on your water supply.