is it the same definition for both words?
They are different and can be one in the same.
A symptom (from Greek σύμπτωμα, "accident, misfortune, that which befalls", from συμπίπτω, "I befall", from συν- "together, with" + πίπτω, "I fall") is a departure from normal function or feeling which is noticed by a patient, indicating the presence of disease or abnormality. A symptom is subjective, observed by the patient, and not measured.
A symptom may not be a malady, for example symptoms of pregnancy. One could debate, however, that this is an example of common misuse of a word, as the majority of symptoms and the history of the word are related to malady. The proper word for such situations would be "indication" or "suggestion" or simply "sign".
A symptom caused by an illness or a drug; "the effects of sleep loss"; "the effect of the anesthetic" black tongue, furry tongue, hairy tongue - a benign side effect of some antibiotics; dark overgrowth of the papillae of the tongue. Side effect - any adverse and unwanted secondary effect;
so for example: the symptoms for fever is..disyness , vomiting, and headache? and for side affects..
Side effects may be caused by the medication you are using to treat the hay fever.
When copying and pasting from another source, it is necessary to cite that source.
A symptoms is a cause of an illness, a side effect is a cause of a treatment.