Cough, cold, and phlegm for 4 days are most commonly due to a viral infection like Common Cold or early Bronchitis, and it is not unusual for symptoms to persist for a few days even after taking medicines like Coldact or Sinarest. The best approach is supportive care: take adequate rest, drink plenty of warm fluids to help loosen phlegm, and use steam inhalation to relieve congestion; a suitable expectorant or mucolytic syrup (as advised by a doctor) can help bring out phlegm, while paracetamol may be used for fever or body pain if needed. Antibiotics are usually not required unless there is clear evidence of a bacterial infection. Avoid cold drinks, dust, and smoking, and monitor your symptoms; if they last beyond 5-7 days, worsen, or you develop high fever, breathlessness, chest pain, or thick yellow/green sputum, you should consult a doctor for further evaluation.