Gastroenteritis: This is the most likely diagnosis given the patient's symptoms started after eating at Taco Bell, suggesting a foodborne illness. The symptoms of abdominal pain, emesis, and inability to keep anything down are consistent with gastroenteritis.

Food Poisoning: Similar to gastroenteritis, food poisoning is a likely diagnosis given the temporal relationship between eating at Taco Bell and the onset of symptoms. The specific type of food poisoning (e.g., Salmonella, E. coli) would depend on the contaminated food item.
Acute Gastritis: The patient's symptoms of abdominal pain, emesis, and chest pain could also be consistent with acute gastritis, possibly caused by the spicy or acidic food consumed at Taco Bell.
Viral Gastroenteritis: This is another possible diagnosis, as viral gastroenteritis can cause similar symptoms and is highly contagious.

Myocardial Infarction (MI): Although less likely given the patient's age and the context of eating at Taco Bell, it is crucial not to miss an MI, as it can present with atypical symptoms, including chest pain and nausea.
Pulmonary Embolism (PE): PE is another critical diagnosis not to miss, as it can cause chest pain and anxiety, and although less likely, it is a potentially life-threatening condition.
Appendicitis: While the patient's symptoms do not strongly suggest appendicitis, it is a diagnosis that should be considered, especially if the abdominal pain is localized to the right lower quadrant.

Inflammatory Bowel Disease (IBD) Exacerbation: Although less likely, an exacerbation of IBD (e.g., Crohn's disease, ulcerative colitis) could present with similar symptoms.
Eosinophilic Esophagitis: This rare condition could cause chest pain and difficulty swallowing, but it is less likely given the acute onset of symptoms after eating at Taco Bell.
Hernia: A hernia, particularly a hiatal hernia, could cause chest pain and abdominal discomfort, but it is a less likely diagnosis given the context of the patient's symptoms.