Pollination is key, yes, but
Pollination is key, yes, but there are lots of reasons that fruit may fail to set, including cool spring nights (it's not summer yet), daytime temps over 90°F, rain, low humidity and high humidity, low light intensity—even smog, according to one source (this might affect light intensity). Try shaking or vibrating the plant in midday, when temps are warm and humidity is low.