Shoulder "popping"?

I don't know if I am imagining it - but in the last week or so it sounds like Chloe's shoulder is popping when she walks.  Similar sounds to if you pop your knuckles - it doesn't happen on every step - but will pop like 5-6 times and then stop, and then again a few times, then stop.  I don't know - maybe it is her leash.  I notice this when we are on walks.  I don't notice it when she walks through the house, but I am not usually right beside her when she is walking inside.  She is not limping.

Should I mention something to the vet?  Is this anything to worry about?  We have an appointment next week to follow-up on the giardia and to complete her vaccinations.