I've been feeling something deep in my right nostril and smells musty for the past few months. i also feel pressure in my right eye. possible causes?

Sinuses: It is a sinus pressure most likely related to allergy. Take Benadryl (diphenhydramine) at night. Take non drowsy allergy medicine like Claritin/Zyrtec/Allegra during the day.. Take a large tablespoon of your local honey everyday. Relax,sleep well,breath slowly.

Infection vs. other: Months duration could indicate infection (bacterial or fungal). Chronic Sinusitis would be near top of the list. Also consider a lodged foreign body (like a bead, other). Lastly, some rare conditions such as Wegener's Granulomatosis or even underlying tumor can cause those symptoms. I would see your doctor (or ENT). Consider imaging (CT scan) and direct visualization -- then treat accordingly.