In reply to Jack McKechnie:
Hi,
I had a similar problem. I couldn't bend my finger and could not go any where the pad of my hands. In fact, my middle PIP joint was incredibly swollen.
For me it was a serious tear of the collateral ligament (it wasn't serious at first but then I ignored it and made it considerably worse and had to take 6 months off).
Get it seen by a professional - my guess is that it's either a collateral ligament tear or general join inflammation caused my overtraining and not enough quality rest.
There are many possible things that may have contributed to this injury.
1) You're not taking enough rest. Your body only gets stronger when you're resting.
2) You're crimping too much.
3) A few sudden slips especially on fingery sidepulls or finger cracks may have shockloaded the ligament.
I'd do the following:
1) Get seen by a professional. Only they can truly confirm your injury.
2) Get yourself Dave Macleod's injury book. He really does explain all the possibilities very well and on a couple of occasions I have found it quite easy to guess what the problem is.
3) Climb on jugs for a few weeks (believe me, I wish I did that rather than having to end up taking 6 months off) and see how it develops.
4) If you're climbing as hard as ever, you're not really allowing the injury to heal and likely to be causing microdamage to your soft tissue at a faster rate than before.
Good luck!