i have a bubble in my mouth that reoccurs requently, mostly after eating

I have a bubble filled with fluid that reoccurs in my mouth 

here is link to a picture of it here http://imgur.com/DLugFJf

you can see the  white bubble on the top right of my mouth. It usually occurs after I eat, and often occurs after I eat somethign spicy.

Tehres not irritation or pain but theres liquid in it when it pops. 

I often pop it by force since it bothers me in my mouth