I wish I would have known about using essential oils for sinus congestion when I was growing up. I had chronic post nasal drip that was so very irritating! Eventually I learned that stress was a huge contributor to this problem. Now I understand that it was my body's attempt to "swallow the tears" when I was in an emotional or stressful situation. Even excitement or anticipation could trigger a horrible bout of the drip. Here are a few other things that can add to sinus troubles:
When my throat starts feeling scratchy (not even really sore yet) and my glands start feeling a bit enlarged, my first essential oil choice is a drop or two of Purification blend (contains lemongrass which is anti-inflammatory and promotes lymph flow) or R.C. blend in a few drops of jojoba oils rubbed gently with downward strokes from temples on both sides of my neck below ears. I also suck on an Thieves essential oil hard lozenge which really helps if my ears feel like they could plug or ache. Getting the lymph system moving can ward off a full blown head cold or sore throat.
Gargling with Melaleuca alternafolia or thieves blend can help help kill bacteria in the nose, ears, and throat. I just drop one drop of either of these essential oil supplements on the very back of my tongue and hold it in my mouth, mixing with saliva for several minutes, then swallowing. This is very effective when started at the very first indication of infection and repeated 3-4 times for the first hour, then once an hour until symptoms subside.