I've had OA for over 3 decades. I also have carpal tunnel (neuropathy entrapment), which complicates things.

I've had to go back to my wrist splints this week, due to more working with trowels, in the garden, etc, and noticed that my hands are not so swollen in the morning, and are less stiff. So some of your pain may be coming from the wrist.

I also have Heberden's nodes on my thumb and first 2 fingers of the right hand, and now one on my middle finger of the left.
They tend to hurt when they come up, but stop after a while and then just get stiff.

It used to be thought that OA was wear and tear and age related. But new thoughts are that it is a systemic disease, and the mechanism is not well understood yet.

I find that antioxidants, and fish oil (or now I am trying Krill oil) help alot with the inflammation and pain.

You might want to check your Vitamin D levels. I have had much less stiffness since going on 5000IUs daily.