Chronic allergy sufferer here so I’ve tried A LOT of remedies. Here’s what worked for me. Some were already mentioned.
Cetirizine DAILY. It only works when it’s built up in your system. It’s not like a pill for headaches that works almost instantly.
Essential oils (EO). This was the game changer for me!
Eucalyptus globulus EO - to relieve congestion place 1-2 drops in a bowl with 1 cup of hot, steaming water. Put your face close to the steam and drape a towel over your head with the bowl. Do this for 5-10 mins. Works every time for me! **Eucalyptus is not recommended amd can be dangerous for children so be cautious around them when using.
Peppermint EO - diffused or inhaled (added to an inhaler stick like the Vicks inhaler). Expectorant, helps unclog, but not as powerful as eucalyptus. Smells wonderful though.
Any immune building EO blend - Diffused throughout the day. Ex. Lemon, Young Living (brand) Thieves blend, Lavender, Frankincense carteri, Rosemary, Tea Tree, Sweet Orange, etc.
This is a weird one but it helps. Before going outside to brave the pollen, or in my case before going to someone’s home where there’s a pet (highly allergic to dogs!), put some petroleum jelly inside your nostrils. That sticky stuff traps the allergen and possibly prevents it from getting intl your system.
Hope that helps!
For the peppermint EO, I have a lotion by C.O. Bigelow that has mint in it, and I sometimes just put a bit just below my nose so I breathe it in. If I've been sniffling and blowing my nose a lot, so I'm chapped, I'll just smear Burt's Bees lip balm (which also has peppermint in) around my nose. Both of these help with opening up my airways a bit, and the Burt's Bees has the added benefit of soothing chapped skin.
For the pressure, I second KF's sudafed-from-behind-the-counter... the real stuff, with pseudoephedrine in it. The stuff you can just pick up off the shelf is not nearly as good. If you notice that it's drying you out
too much (which can also cause sinus pain), try to find diphenhydramine HCL (in the US, it's the active ingredient for Benadryl; I think over here it's sold as a sleep aid... and it will knock you out, but it's very good at inhibiting the histamine response. Try taking it at night and the sudafed in the morning, maybe?).
And I also use Cetirizine daily. You can get a 28-day supply of generic stuff for, like, £2, I think. But as noted above, it's a long-term maintenance medicine, and won't be a quick-fix for immediate relief.