Hi! You have not mentioned if you ate anything from outside shop a day or two before. Most likely you have got a food poisoning due to ingesion of stale/infected food. Any kind of infection in the body will give rise to fever, and so you had a head ache and body ache with variation in your body temperature. If fever troubles you, then you should take a tablet of paracetamol/acetaminophen. The hot and cold flushes you get could be due to excessive sympathetic activity. Your treating family physician may advise you for getting a routine test of your stool or blood sample apart from prescribing you an appropriate antibiotic and some anti spasmodic if the abdominal pain is severe enough to warrant it. If you get nausea/vomiting which you might, then go for an anti emetic. At the same time maintain your hydratioin by taking enough liquids ( small quantity frequently) mixed with some electrlyle powder available over the counter. If the pain increases and you do not get relief even after these efforts, then you should consult a general surgeon, who may advise you for an ultrasound and other necessary test which can be decided only when he examines you. Take care.