Slipping Around

My shoulderblades seem to slip around?
I’m not sure if this is worth the question, but i’ve always been pretty flexible. I can stick my shoulder blades out at will, I can push them out, push them out to the sides and force them inwards up against my back.
Recently I went away and got a back massage; the person doing it was utterly amazed at my shoulder blades just slipping around my back as he massaged? It doesn’t hurt but I can feel them. Is this a common thing or..?
Some people have hypermobile joints (extra flexible) just by nature. It isn’t something to be concerned about, it’s more a function of genetics, and not an illness or problem unless it is causing you pain. I don’t know how common it is, but it’s definitly not anything to be worried about.
Jimmy Wakley ~ Slipping Around