I assume that "burping" means depressing the valve head to get everything moving....

I have had the same issue on occasion. Sometimes the valve gets stuck. I don't know which tubes I have. (I usually get what's on sale), but by unscrewing the stem valve and depressing usually allows me to pump it up.

What sort of pump do you have. There is a possibiltity that it may be your pump valve head. I use a floor pump 90% of the time.