A stomach ache yesterday and continous fever till the morning and now just body pain all over what could it be??

Stomach ache/malaise: Did you have diarrhea/ vomiting? May be gastroenteritis and today you have malaise from all the vomiting /diarrhea and electrolyte loss. Would replenish with pedilyte / gatorade. Sometimes I have seen strep cause abdominal pain with some vomiting or no vomiting) H pylori, a gastritis bug can cause abdominal pain and malaise, fever is rare . F/u/ w/ doc as older individuals can have other issues

May be a virus...: or it may be food poisoning, or it may be a urinary tract infection, just to name a few possibilities. I suggest getting a physical exam and a urinalysis if your symptoms continue beyond another day (sooner if you are worsening).