Please explain why is food poisoning so painful?

Poison.: When your body is poisoned by foods, the body reacts in two ways, it is hurt by the poisons the foods have, and some cells can be damaged or die in the process, and this can cause pain. The second is the body fights fiercely to get rid of it, which includes acid production and sometimes vomiting and diarrhea to flush the poison out of the body as quickly as possible.