Firmness under right jaw

Hello, everyone.
Right under the corner of the right side of my jawbone (I guess where my submandibular gland is?) feels more firm than the left side. I could feel the difference especially when I tilt my head back to feel my neck. It doesn't really feel like a lump- but its just noticeably harder there when I press down. There is no pain at all, either. Although lately my throat has been feeling a little tighter than usual, and I lose my breath a lot quicker. I do feel as though my nose and throat have accumulated more mucus than usual, but I don't know if that's at all related.
This may seem really simplistic, but is it possible that my glands are just really asymmetrical or something and the shortness of breath is something different? My mom says it just feels like a more pronounced tendon or something (...yeah, we're not really medically well-versed). I've yet to go to the doctor to get it checked out. I'm 19, and there is no family history of any kind of disorder or anything.
What could it be?

Of course, I'm dreading the possibility of it being something a lot worse.
Thanks!