Hello farrellwheeler welcome to HCM,
Diarrhea with burning sensation in stomach may be due to Gastroenteritis
, peptic ulcer disease
, etc. Your headache and body ache
may be due to your stress but not exactly..These are not serious conditions and need not be worried, still if you are too much concerned you can have an upper gastrointestinal endoscopy and rule out other causes...