I think this is arthritis? Left index finger pain
When I was in seventh grade (13 years old - now 24), I noticed that whenever I moved my index finger, I could feel a small grinding inside the palm knuckle. Fast forward a few years to when I was in tenth grade, I was riding my bike on a dirt road and, every time I ran over a bump, my fingers would wiggle around and it was causing severe pain in my left index finger. It felt like there was a large quantity of something stuck inside my knuckle that hurt every time I moved that finger. I later noticed that, if I cracked that knuckle by pulling the finger out, it would end up feeling, once again, like there was something stuck inside that knuckle. But, if I made a fist and just used my thumb to pull down on that finger to crack the knuckle, it made the pain lessen for a while.
As of late, whenever I've been playing the guitar (I've been playing for almost 20 years), or when I'm picking up something large, or just doing anything that needs me to use pressure while keeping my finger flat, I'm getting that same "there's something inside my knuckle" kind of pain.
Is this arthritis? Is there something I can do about this? I don't want to stop playing the guitar and making music, literally every facet of my life revolves around the music I make and I can't give it up. I had to quit singing when I had surgery on my lung last year and that was hard enough on me, but I don't think I'd ever be able to give up my music.