Small white bump in mouth, comes out when I sneeze or cough, comes back every month or so, what is it?

I keep getting this little white bump in the same place in my mouth, on the right side, almost in my throat, just far enough to the front that it brushes against my tongue and really annoys me. It must be a growth or something that gets stuck there, because it will come out sometimes if I sneeze or cough, or if I get it out with a toothbrush. It's really small, and looks like a little piece of food, or wax, maybe, it's solid but not too hard. Then it'll reappear in a month or so, always in the same place, and it's always the same once it gets out, little, waxy, and kind of hard.. When I was at the doctor's office for the flu, I had one at the time, and I coughed, and it came out. I showed the doctor, she said it was a something-lith, but she couldn't remember the real name for it, but apparently it's not dangerous or anything. I tried researching it, but I couldn't find anything, What is this thing?