Summarize the following:
Tell your doctor what is bothering you in detail. Have you always had sinus issues or is this a new problem for you? Do you find that you feel better or worse at a certain time of the day? How are you currently finding relief? Be specific about your symptoms because the more details you provide your doctor, the better equipped they will be to help your particular condition.  Other questions your doctor may ask: Do you have drainage? If so, how much and how frequent? What is the color and consistency? Do you feel facial pain or fullness? Reduction or loss of smell? If any of the following are present, you may have a condition more serious conditions than sinus congestion that needs immediate treatment: high fever, double or reduced vision, swelling around the eyes, pain when moving eyes, severe headache, stiff neck that is painful to move, or significant or recurrent nosebleeds. Before your doctor suggests medications or other procedures, they will likely perform a visual test. Looking into your nasal passages with a lighted scope will let your doctor see any irritation or surface level problems with your nasal passages. If necessary, your doctor may refer you to an ENT (ear, nose, and throat) doctor. If your doctor recommends this test, they will prick your skin with small needles containing various allergens. If you show an allergic reaction to any of the prick points, then that will let your doctor know that you are sensitive to that particular allergen. This is helpful because it will let you know that you need to avoid pollen, for example, while you might be able to tolerate other kinds of potential allergens. For an allergy blood test, the idea is similar to that of a skin prick test. If your doctor recommends this test, know that the key difference is that rather than pricking your skin, your doctor will draw vials of blood to test for allergen sensitivities. This test is less accurate than skin prick tests, but it is still useful and widely used. Allergy blood tests are often used in children and others who might have complications or problems with the skin prick test. To get a clear image of what might be wrong with your sinuses, your doctor might recommend a CT scan. These scans generate an image of your sinuses, so your doctor can see if your issues are being caused by a physical problem like a deviated septum. If your doctor sees no physical problem, then they can rule out physical causes of your sinus problems.

Summary:
Talk to your general practitioner. Have a visual inspection of your nasal cavity. Take an allergy skin prick test. Have an allergy blood test. Undergo a CT Scan.