You should go to specialist and do x-ray of your finger.
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My left index finger hurts on the middle knuckle. It started about 24 hours ago, out of nowhere. I was just sitting at my computer, and the knuckle hadn't been injured or overworked in any way. It doesn't hurt as long as I don't move it, but if I apply a slight amount of pressure it hurts tremendously. If I apply more pressure, it starts hurting less. Heat or a vibrating massager also temporarily stop the pain, but it resumes within a minute after I stop. I'm pretty sure I have rheumatoid arthritis genetically, and this is showing symptoms of that so far.
Could it be something more serious, and what can be done to treat it?
dear you should contact with a doctor because the Injury to any of these components results knuckle pain. This joint is also prone to fractures and dislocations. Knuckle pain and swelling can originate from several causes.