I have 4 fingers the index and middle fingers that over time have started to curve inwards, why is this ?

I have been working with my hands for nearly twenty years as an artist and picture framer. For most of those 20 years I haven't had any real problems except for some pain and swelling of my joints, but the last job I had required me to use a staple gun and canvas stretching clamps for nearly 6 hours a day when packing up finished artwork and stretching canvases. The other framing jobs didn't require me to package items where I had to squeeze and grip a staple gun for hours at a time all while standing on concrete for 7-8 hours a day, not every day of course but at least 3-5 times a month. After a few hours of doing this my hands became very cramped, my joints would swell and this became quite painful. Even the next day it was so hard to use my hands as my hands and arm became numb, usually my right hand, even opening the door or a jar would be very difficult to do. I even got fired for calling in sick because my hands were numb and pretty useless since holding and gripping frames was my job. My fingers became curved, both the right and left hands, the index and middle fingers. This has never happened before and there is no one else in my family that has this issue. I was told it could be early onset arthritis, on some days when I don't do any work work with my hands my joints feel like they were being stretched even when just opening and closing my hands, on other days when I had to wring out clothes or rags for instance, my knuckles would swell up and sometimes go numb. The only thing that would help was taking pain killers, not as strong as morphine or oxycontin but diluadid, something without acetaminophen since it upsets my stomach and is very bad for your liver, but the opiate itself is not nearly as toxic as all it does is trigger your own bodies seraton and dopamine. I know all the issues but I need something for the pain, I prefer the natural opiates over the hypocritical pharma ones since they contain the other liver killing chemicals. Yes, one is illegal although our government is "secretly" smuggling them in anyway, I also hate big pharma as they are killing and hurting millions of people legally while the natural forms for some reason are illegal. Hmmm, nothing to do with money eh? Anyway, my arthritic and curved fingers need an answer, is there any one out there?