There is a small bubble at the back of my mouth, that's irritating until I pop it. What is it?

It's located at the hinge of my jaw, on the part between my two rearmost molars.



It's not a zit. It pops similarly to a a bubble on bubble wrap, and produces a liquid similar to saliva but more slimy.There is a small bubble at the back of my mouth, that's irritating until I pop it. What is it?
maybe a mucus bubble, something like that, im not sure, that is a very hard question to me.