I have if I sleep more than 4 hours at a time or so... weird.
It could be candida. there are protocols for this on the forum somewhere.
Mine seems to be exacerbated by sugar and dairy products.
If I eat sugar, or sugary fruit such as dates, then I get mucus at the back of my throat within 10 seconds. More sugar = more mucus. I'd like to know why it happens, and why so quickly. It didn't happen before ME.