Hmmm do you think it's a physical pain or something that manifests from your emotional state?
I know when I'm imagining/fantasizing a scene of my own submission I feel really good, but can take it so far that I get sort of upset because I don't have a dom and have to real myself back in before I take myself too far. Does that make sense? I'm not sure if this is the same as what you're feeling or if it was helpful to you, but I hope so. haha