Eucalyptus is the best thing I know for congestion. You can put 15 drops of eucalyptus oil into a humidifier if you have one, or 10 in an oil diffuser, if you don't have either of those you can take a steamy bath and put the oil in the bath, breathe deeply while you're in the bath to help clear your airways.
Another thing that helps me with congestion is drinking hot peppermint tea, and local honey always helps when it comes to congestion and allergies.
Interestingly enough, the main ingredients in Vicks Vapor Rub which many people use for congestion are Eucalyptus oil, Camphor oil, and menthol. It is definitely a less natural remedy though as it contains petrolatum and a synthetically extracted menthol product.
Most cough syrups have cough suppressants in them as well as a sedative, this doesn't really help with congestion. Some syrups contain medicines that loosen phlegm but they are far and few between. Also some people prefer natural remedies to store bought ones that often contain things that aren't great for our bodies while costing us much more money in the long run. I remember going to the store to buy some over the counter allergy medicine recently and was blown away by the insane prices. I turned around and bought nothing rather than spending that much.
Eucalyptus and Lavender didn't work at all with me. Starting out be congested with the sinuses and then if not stop it travels down in the chest area where the phlegm causes more problems.
The things I did before itstarts traveling to the chest area is using wintergreen or peppermint essentialoils in a water diffuser that way the inflammation in the sinuseswill stop flaring up. Another method I use is high gauss magnets roughly around 3,000. The magnets increasethe oxygen flow and soothe the pain. Either buy a mask or make one yourself that would be not so expensive. Make sure it's on and around the sinuses cavity. Also, it's a good idea to blow all that stuff out and boost the immune system up.
With the chest congestion, I used raw natural honey from a local bee farm and lemon juice in warm or hot water. Breaks up themucus and phlegm in the chest area. Hope my experiences may help you with your problems. I've always had sinusitis where if not treated in early stage becomes a congested chest problem. Even though I don't get the commoncold but the sinus colds are the worst.