Painful lump on my finger

Hello I've been getting very stiff finger joints over the past few months. About 4 weeks ago I started getting pain sporadically, on my middle finger, on the joint near my nail. It's like a sharp stabbing pain. Lasts anything from 1 minute to about 15.! There's also a lump on the side, which is where the pain is aswell.

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Could this be Osteoarthritis.? I'm 51..and female. Should I see my dr.? I have added a picture..hope you can see where I mean.!