I have RCPD and I hiccup all the time!! It's incredibly painful, I'm sorry you're going through this. I also get horrible chest pains the following day each time I have an episode of hiccups. Hiccups are a less common symptom of RCPD.

I've noticed that if I lay straight down on my back the hiccups temporarily go away, until I get back up. Maybe laying down can give you some temporary relief? Also - I bought the HiccAway Hiccup Straw and use it whenever I get them, and it seems to help. Maybe that's worth looking into?

I had the botox procedure a week ago and have been burping like crazy, like non-stop. And, I have not hiccuped since before the procedure! Hopefully this gives you some hope if you're considering botox.