4 fillings in June. Sensitive teeth, headaches, earaches, sore throat, post nasal drip, and slight chest and head congestion ever since (3 months)?

2 unrelated issues. and should be treated separately. See your GP for headaches, earaches, sore throat, post nasal drip, chest and head congestion. You should see your DDS for sensitive teeth or other dental problems.
Different Problems. Sensitivity, headache, and possibly the earache can be caused by deep restorations that have inflamed the nerves in your teeth. Your other problems are most likely unrelated. Have your dentist check your sensitive teeth and see your physician for your other problems.