This weekend I had a sore throat, upset stomach, and an off/and on again headache. When it came to the headache, I had tried tylenol but there was no change. I have avoided nasal decongestants because I want my body to function by itself, but with the illness, I needed extra help. Once I took a 12 hour ill, the mild congestion (one nostril at a time) cleared up fairly fast. Within a few hours the headache dissipated and has been gone since (24 hrs). For some reason, despite the location of the congestion (right or left nostril), when I get congested, pressure builds up in my nasal sinus cavities. This pressure leads to painful headaches.
Since my summer sinus surgery, I haven’t had many headaches. But then again, when my allergies kick in, I find that I drain fairly well. But without a doubt, sinus headaches can be resolved at times with decongestants.