I have bad allergies - they hit me like the flu.
I did the allergy test thing. Yes, they use pins, but it isnlt like being pricked 100 times. The worst thing about it is the pricks will cause swelling and itching. That's how they find out what you are allergic to. I chose not to go the route of shots. I learned how to deal with it without prescription drugs.
Here is what I do. During periods when I usually get hit hard by allergies (May and Aug-Sept), I take claritin, which is no longer a prescription drug. You can buy it over the counter for about $14 for 90 tablets. Each tablet lasts 24 hours and does not cause drowsiness. Claritin is an antihistimine, and as such it is great at preventing allergy attacks. I get it at WalMart under the Equate Label. I dont use the brand with a decongestant, because that may cause drowsiness.
Still, it does not handle congestion. If you prevent an allergy attack, you will reduce congestion. You should also keep your home's filter's clean, keep your carpet vaccumed, and don't keep furry pets in the house. Keep your house dusted, including beneath your son's bed. Consider buying an air filter, too, for his room. Encourage him to take hot showers and keep his nostrils clean of pollen and dust. I know it sounds gross, but I will clear my nostrils with tap or shower water. Be careful not to snort it down, because it will be uncomfortable.
I use an inhaler during the worst days, as needed. I use a nasal spray at times, but be careful. Those things can cause more problems than they solve/ I use a generic, over-the-counter 12 hour spray when I have trouble breathing through my nose (usually at bed time).
It wouldn't hurt to take your son to an allergist, so he could find out exactly what your son;s allergies are, and he could advise you of current remedies (other than mine).
Good luck!