Getting sore throat monthly once. This?

Hi Sir/Madam, Regularly I am getting sore throat and light cold monthly once due to water change or weather change or if I take any sweat items or cool drinks. Due to sore throat I get fever, body cold, body pains, watery eyes and heavy runny nose. I am heavily suffering with these symptoms regularly.i am getting this issue regularly monthly once for sure since 10 years. I consulted many doctors in my hometown. Doctors says it is a bacterial infection and viral fever. I take the following medicines and dosage when I get sore throat and fever symptoms 1. Dolo 650 3 times per day after food 2. Montair - LC (montelukast 10mg + Levocetrizine 5mg combination) daily 3times per day. Could you please suggest me the permanent solution for this?