Fever with body ache plus a runny nose and cold for two days is most likely a viral upper respiratory infection or seasonal flu, and it usually settles in 4-5 days. Since dengue is also doing the rounds right now, a fever crossing day three without any cold symptoms improving would need a blood test. For now paracetamol 650 mg when the fever is above 100, steam inhalation, and 3 litres of fluids a day is all you need. Avoid antibiotics at this stage; they do nothing for a virus.
Next Steps
If the fever is still there on day 4, get a CBC with dengue NS1 and a malaria smear. Go to a hospital right away for breathlessness, chest pain, persistent vomiting, bleeding gums or dark red spots on the skin. If you would rather not wait it out, consult me online and I will put you on a proper prescription today.