It certainly IS your place to say something to her Dad... your her parent too. It can't hurt to get it checked out (just in case)-- and if it is nothing, and only a nervous habit, then you can deal with that seperately. My SD has had some really odd behaviors due to anxiety (in the past when she was younger)... for weeks one time she complained of a "lump" in her throat... there was nothing there of course, but literally, EVERY night (especially right before bed)- it would be there and bothering her. Eventually, she got over it and it miraculosly went away... but it took time. She's had issues like this since she was very young though- due to the stress her own mother caused her... which, in turn, caused her anxiety. So her situation is a bit more unique.
Children though- can "act out" in many ways... sometimes they complain of aches or pains that aren't really there- or they think they are because they want that attention. It's not that uncommon. Most likely it will go away on it's own- but sometimes they just want to feel heard and comforted... then they feel better.
We try not to feed into our kids complaints when we know it's not real- but there have been times we took her to the doctor so she had that reassurance all was OK (not often- only maybe once or twice). And that was when something continued for a long time and all our reassurance was not cutting it.
Just my two cents- but it can't hurt to maybe ask your OH if maybe it would be good to have her checked. Might actually help for her to hear it from a "professional"-- but that is certainly your call. You know your child best and should do what you feel is right. But if there truly is something causing her discomfort, then you'll know and can get it fixed.
Best of luck!!!