What Causes Pain While Swallowing?

It hurts to swallow, like there is some sort of blockage in my windpipe. I burp, but it dosen t relieve pressure and I have been burping for hours on end. A deep breath causes me to trap air in my esophagus as well. I can feel it, I don t think it even reaches the flap that closes off the stomach/ lungs to certain items. It s only a fraction of the air, but It has been reoccurring as long as I can remember.