It is certainly possible that the meningioma is the cause of your constant frontal headache and tension in your head. I would talk with the doctor who is taking care of you about these symptoms. There are several possible causes of the nasal swelling. One possible cause is that there is a nonallergic condition where the blood flow increases and creates all the symptoms that you have described. It is called vasomotor rhinitis. Please read our allergic and non-allergic rhinitis information at http://www.nationaljewish.org/disease-info/diseases/allergy/about/conditions/rhinitis.aspx to learn more. It is possible that the meningioma influences this, as well. I would suggest that you ask your doctor the same questions that you have asked in this forum.
It is not a good idea to use phenylephrine spray chronically. It causes "rebound" swelling of the lining of the nose. After taking it daily for a prolonged period, you will need to work with your doctor to allow you to withdraw from its use without the nasal swelling being a major problem as it has been for you in the past.
A prescription nasal steroid spray decreases the swelling of the lining of the nose and sinuses. This is a better long-term treatment because it does not cause the “rebound” swelling. However, unlike the phenylephrine spray, a nasal steroid spray does not provide immediate relief of symptoms. It may need to be used every day for several weeks to months for it to help. To help the nasal steroid spray work better, use it regularly after doing a nasal wash to remove mucus from your nose and sinuses. This could help to stop your constant frontal headache, tension in your head, and allow you to smell again. Please read our nasal wash treatment information at http://www.nationaljewish.org/disease-info/treatments/alt-ther/nasal-wash.aspx to learn more about this technique. Share this information with your doctor to see if doing nasal washes regularly would be helpful for you.