It is very likely that you are suffering from allergic rhinitis, or nasal allergies. This is a very common condition, which is generally provoked by allergens entering the nose by inhalation, settling on the nasal lining, and provoking swelling and an inflammatory response. The symptoms are nasal congestion, sneezing, runny nose, and the like.
Fortunately, allergic rhinitis is a very treatable condition! I would suggest that you start by going to see your primary care doctor
, as they will help you decide how best to approach things.
Medications that are used to treat allergic rhinitis include antihistamines like loratidine (Claritin) and cetirizine (Zyrtec), which work by reducing itching and swelling. Another set of medicines that are very helpful are inhaled nasal steroid sprays like fluticasone (Flonase) and mometasone (Nasonex).
Some home remedies are also very helpful. In particular, irrigation of the nose with saline can clean out mucus and allergens. You can purchase a nasal irrigation kit inexpensively in your local pharmacy.
Also, it can be helpful to try to identify the source of your allergy. For example, if you mostly have symptoms at night or when you wake up in the morning, this would suggest that you are allergic to something you are exposed to in the bedroom, such as mites or mold.
Talk to your doctor, who will have other suggestions for you!