Stuffy noses and sinuses are the bane of many millions of sufferers. There are many reasons for congestion, ranging from short lasting colds and viruses, to longer lasting bacterial infections, as well as an number of irritants. Irritants can range from allergens such as pollen, mold, dust, and work-related exposures to chemicals and supplies.
If the reason for swelling and inflammation can be found, sometimes an allergist can provide relief by reducing your sensitivity to the allergen. This can be done with allergy shots -- desensitization via a series of shots that can eventually decrease your irritation significantly, even curing your allergy.
An adjunct treatment strategy is to fight the inflammation outright. Options include nasal rinses, antihistamines, leukotriene inhibitors, and anticholinergics.
The most effective (and annoying) treatment is to wash away the irritants that are causing the inflammation. You can buy saline lavage kits over the counter, which you mix with distilled water and squirt into one nare and it runs out the other. In last week's episode of Grey's Anatomy, this is the penance that crackerjack hardass surgical intern Yang was obliged to do in the ER since she didn't show enough concern for the patient with persistent nasal congestion (and it turned out to be leakage from the patient's spinal fluid! this isn't likely in your case, but highlights that you need to get checked for persistent symptoms!!)
Another treatment is antihistamines which are very accessible now that they're over the counter. Antihistamines block the hormone histamine which makes you itch, and do so very soon after taking the pill. You've seen the ads for Claritin tablets ("blue skies, nothing but blue skies"), but did you realize that the raw ingredient is loratadine, which is found in any number of over the counter, incredibly cheaper antihistamines such as Alavert, Walltrin, Allerclear (Costco), and others. A prescription alternative is an antihistamine nasal spray Astelin, which I find much more effective, but can cause a bitter taste if you sniff while squirting (so don't sniff!). A great reason to use Astelin rather than a nasal steroid is that regular use of nasal steroids can cause epistaxis (nosebleeds) whereas Astelin doesn't have this risk.
Which brings me to steroid nasal sprays. This is the cornerstone of treatment of rhinitis, because of it's effectiveness and satisfaction of users with respect to length of relief. Whereas antihistamines wear off from their hormone receptor blocking effects relatively shortly, steroid sprays are longer lasting and often only need to be used once a day or every other day. Although in the past we've thought it takes up to a week to start feeling the effects, this seems to vary for folks, and especially for those who've used it in the past, it can start working pretty much right away. You don't have to worry about steroids affecting the rest of the body, it's limited to the sinuses. When the effect of more potent inhaled steroids were studied in children, any effect on their growth was made up later in adolescence. You do have to worry about nosebleeds as I mentioned above. I'm sorry to say I have a terrible habit of picking my nose... yes, I try not to but I have terrible allergies and try to get rid of the crud in this less wholesome way. So, take it from me, don't pick your nose if you need to use nasal steroids. You're sure to bleed. Even without picking you can bleed, and one way to avoid nosebleeds is to try to spray towards your ipsilateral ear with your head tilted back 45 degrees. That way the spray is away from the middle, where most people bleed from.
Anticholinergic sprays such as Atrovent are rarely used, but in chronic refractory cases, it can help dry out the sinuses. It comes in 2 strengths.
Oral steroids are the most rarely used in my practice of Urgent Care since I don't see as chronic cases, and when they are used, they're very effective. You just don't want to be taking oral steroids for a long time since that increases your risk for side effects such as water weight gain, mood changes, fat accumulation, bone density loss, skin changes, and vision changes. They're not usually used for a long enough time for these adverse drug effects to happen.
If all of these treatments fail to help you, you may need to see an ENT to get a sinus cat scan to look and see if the ostia (holes draining the bottom of the sinuses) are open or swollen shut. If shut, the surgeon may offer you surgery to drill them open and clear out other polyps and swelling around turbinates. This helps many people, but ask about the likelihood that this surgery would need to be repeated, and with what sort of regularity to keep it open.