Swollen throat diagnosis?!?

So yesterday I noticed that in the morning, my throat seemed swollen a little bit, but it wasn't sore. It hurts when I swallow, but not like a sore throat hurting, like a pressure hurting. It got worse as the day went on, then this morning it was minor again. Now, in the afternoon, it's worse than yesterday, and when I turn my head it's almost as if my whole throat is closed! On the outside it doesn't look swollen at all and my glands are hardly swollen. What could this be? What's it caused by? I'm only allergic to penicillin and that just gives me hives.