I have something similar. A very mild soreness on the left side of my throat that seems to be there one day, and not much another day.
Have you ever took a flashlight and stood in front of a mirror to take a look down your own throat? Does it look red and irritated at the back?
I think one of the causes of my sore throat might be acid reflux (GERD). Look it up online and see if you have any of the other symptoms, and if you do, ask your doc to check you out to see if that really is your problem.
Also, what made you think of a blocked gland or node? Do you have any enlarged lymph nodes on your neck head or jaw? If you do, bring that up with your doc as well.