Welcome to the 40s although you got there a couple of years early. I use to LOL at joint pain until I hit 41. I live on Anit Inflammatory now.
It's a real deal and most everyone gets it depending on how active you are/were. It seems the more you abused your body younger the quicker you get it.
I just had shoulder surgery and one of the things they fixed is what they call 50yr old shoulder. You get it between 48 - 52. It's sort of like locked shoulder or a calcium buildup (barnacles) and they have to break it off. Nice...