For a headache and severe body ache, you can take over-the-counter pain relievers like Acetaminophen 500mg or Ibuprofen 400mg, provided you have no underlying liver, kidney, or stomach conditions. Please follow the package instructions for proper dosage. Rest and stay well-hydrated. Since severe body aches can indicate an underlying infection like the flu or COVID-19, please consult a doctor if your symptoms persist for more than 3 days, worsen, or are accompanied by a high fever, stiff neck, or difficulty breathing.