Thread: hissing without reason

As the title suggests, lately, Neevie has been hissing without reason - she'll be on the couch, cleaning her fur, relaxed and suddenly "hsssss" then just resumes her cleaning like nothing happened - doesn't happen often, just a handful of times in her 3 years.
I thought she was just quirky, but then this morning she was sitting on the table, watching the birds while I watered my plants, and she yelped in pain and ran away to the door, and hissed again. then looked at me like "what? hiss? me? never..."
I looked on the table, there was nothing she might have hurt herself on...
I'm planning to take her to the vet this week, just to be on the safe side. But if any of you have any idea/suggestions on what to check, that would be welcome.
When we got her, the breeder did warn that she was born with a small hernia, but then our vet didn't notice anything and suggested it might just have resorbed itself. So that's the first thing we'll check, methink.