my son had that same problem when he was younger it sounds like u have a small yeast infection in ur mouth its called thrush but they put my son on antibotics an he got better in no time i hope u feel better
It sounds like a possible thrush infection, but very well could be something else. I suggest you see your doctor for accurate diagnosis and possible script for an anitfungal. I have successfully treated mild yeast infections with slightly hypertonic salt rinses - about 1/4 tsp salt in 6 oz of water.
Take care.