A Pit is common in some fruits. Cherries, avocados, and peaches are some that all have a pit..A pit is the part of the fruit that protects the seed until growth time. A very hard and large pit. It was common for people to choke on them in older times, common enough that the feeling is still used in our language. "It felt as if I had a pit in my throat."

The expression usually appears as ‘a lump in one’s throat’. You could also say ‘I’m all choked up.’ Both expressions refer to that welling up of emotion (usually sadness, but it could work for intense happiness too) that causes a sensation of temporarily being unable to speak.

Thanks for your addition, Gracie. It's really helpful.

Honestly, that phrase doesn't make very much sense to me. Sometimes people say that they feel as though they have a "lump" in their throat (if they feel like they're going to cry). You can also have a "frog" in your throat if your voice changes due to being sick. But I've never heard of having a "pit" in one's throat...I would not advise using that in conversation.

哽咽了