Globs That Drop From Nasal. What Are They? Are They Mucus?

In the past year or so, I have experienced large, scab-like globs that drop from my nasal area (the right side). I can feel them and then see them just near the top of my uvula . I can usually cough a few times and spit it out. For the next minute or so, the area feels a little sore. It seems like mucus is getting caught somewhere in the sinuses and then gets too heavy and drops . It is generally the size in diameter to a dime, yellowish-green in color. My nasal passages seem dry and sometimes appear close to closed. I have always had a sinus drip , but not this collection of mucus. I have looked online for information something similar to this, but have not found anything. Oddly enough, my son and mother experience the same thing; my mother seems to experience it as often as I do (sometimes daily, and other times, every few days). Thoughts?