It probably is osteoarthritis...or fibro. I have some popping in my joints from fibro and also I had very bad pain in my right thumb, to the point I could barely hold a pen to write. I was practicing how to write with my left hand.
I had to have special tools to help me open jars and I couldn't even open my front door because it has a thumb latch. You know what I did? Nothing! Now it's absolutely g-o-n-e! This kind of thing has happened to me sooo many times over the years I've had fibro. I know the doctor thinks I'm crazy.
For example, every summer I not only get a three month long flare but I also get pain in my feet. Two years ago it was my left foot ball joint at the big toe. Last year it was my second and third toes on my right foot. This summer it's my left heel. I don't even mention it because I know it will go away. My cousin has fibro too and I mentioned this foot pain in the summer bit and, believe it or not, it happens to her too! LOL So, don't stress over this. It could very well get better on it's own. Just baby it as much as possible.