ok, what sort of injury did you do to your finger? how long ago, how was it rehab'd? how much climbing have you done on it since?
Do you have any pins and needles, numbness or weakness?
Whwn did you first notice current pain? How has it progressed? is it getting better or worse? did it come on in response to a movement? suddenly? gradually? How can you reproduce the pain? with a certain position, or after a certain length of time bouldering? (try to be specific, how you reproduce the pain is the best way to work out what it is).
How old are you? have you recently changed/increased your training schedule?
It's not always possible (or necessary) to get an actual structural diagnosis. If you take ibuprofen and rest and it gets better in 2 days to a weeks so you can start slowly training again, that's ok. in fact, Drs use this as part of the diagnostic process... if it doesn't get better, then they may need to investigate further. Most likely it's some form of inflammation. Because the muscles in your arms are in sheafs, any inflammation leads to increased pressure, which can give a diffuse ache and pins and needles/sensation changes. This is usually termed compartment syndrome, and the advice is... ibuprofen and rest and gradual return to full activity. It pften comes on in response to increase in training (time/intensity).
If you can answer the above questions (PM me if you like), i may be able to help a bit more.