Hey dear, Sorry to know about you sufferings!  As you have described that you are having this cough, cold, sore throat and fever from long time. I suggest you to get some tests done like chest x-ray, blood tests for allergy. If you are likely to be positive for allergies then this might be increasing your problems. There is patch test also available which can find the specific allergen your body is reacting for.. I will advice to consult a Chest physician who can help you with this. Hope this might help you. Get well soon!