Hello Sir. I'm Dr.Yogesh Kr Sharma. As per your history given,  your son is might be suffering from Malaria to me. In this raining season,  if you have fever with chills and rigors and generalised weakness or Bodyache, this could be Malaria. But your history is incomplete,  like any joint pains. Anyhow you must have Tab. Crocin 500 mg as required. I would like to suggest you the following investigations as follows : 1. Complete blood count ( CBC)  2. NS 1 Antigen for Denue fever 3. MP Antigen and peripheral smear for malaria. These test are utmost necessary and can be done quickly on urgent basis. What is the Body weight of your son who is 15 years old. And also since when,  he is suffering from these symptoms. Right now before the result of investigations, you should have only paracetamol 500 mg as required if fever is there. My clinic is nearby Dwarka sec.13, on Old Palam Road or you can upload the reports and come to practo chat which is also feasible. I think it is Malaria. Please take action as soon as possible. Regards.