First the bad news! You are at the perfect age for this to begin happening. I was 35 when I first noticed right middle finger pain. It was an old injury that I got back in my 20's. It came to revisit in the form of Arthitis.
Now the good news! A few years after this I found a supplement called Glucosamine. Since taking this one supplement my finger has since returned to normal. I know that this one supplement does the trick because I tested it. I stopped taking the Glucosamine for three weeks and the pain returned. It takes about 30 days (give or take) for the supplement to begin helping you. I take three 500Mg doeses per day for a total of 1500Mg in one day.
To add to the joint regime a few years ago I began taking MSM, Fish Oil and Boswellia. Rather than have me explain the benefits of each simply do a google search. The experts can tell you a great deal more than I can.
I will tell you that I am now 49 years of age and I have no joint pain of any kind!