I'm in my 20's and I'm having the same issues. I haven't injured my finger in any way but it's been swelling and hurting more and more each day. It is also my pinky finger, and has lasted for around 3 months now. I have not been to doc yet but my grandmother a retired nurse said you probably just jammed it. Nope did not.... May have to go if it continues to get worse.
time for a new doctor and you should ask him to pay for what you put into for pt! its sounds like early stages of athritis.
I believe you did not jam it. If the first doctor did not listen, I suggest seeing another. Start over fresh and see what you learn.