Hello,
2. The pressure in the left ear could be secondary to the 
nasal congestion and inflammation around the Eustachian tube. 
When the Eustachian tube is inflamed or edematous, the nasal end of the tube gets blocked firmly, thus trapping the air and creating pressure in the middle ear. This can be relieved with steam inhalation and saline 
nasal spray.
3. To discuss the left frontal 
sinus headache. If your doctor has already performed the X-Ray of the 
paranasal sinuses and found out that there is blockage of the frontal sinuses, then the antibiotics and other supplementary medicines may be effective.
 If there is no blockage of the sinuses seen, then the above-said medicines may not work and it may be related to the sudden withdrawal of the caffeine and smoking.
My suggestions to you are:
1. Drink plenty of warm water
2. Do steam inhalation regularly
3. Use saline and a 
steroid nasal spray to relieve the sinus and nasal congestion.
4. Avoid 
pseudoephedrine, this causes more dryness of the 
mucous membrane and may worsen the Eustachian tube block.
5. Get a CT scan of the paranasal sinuses done to identify the blocked areas in the sinuses.
Hope I have answered your query. Let me know if I can assist you further.
Take care
Regards,
Dr Ivan R. Rommstein, General Surgeon