I ate a chocolate and later realised there is living maggots inside. i already ate halve of the slab. my stomach is aching/cramping and i feel sick.

Maggots r edible: It is unlikely that your stomachache is from eating the maggots, as they are edible in many cultures. The chocolate may no longer be fresh, but more likely, you are having an emotional reaction to having eaten maggots. Also, chocolate can cause heart burn in some people, much like caffeine and spicy foods, but you should have experienced this in the past. Oral antacids help that.