You should look into some basic finger and hand grip strengthening exercises. I don't really have any off-hand right now to describe, but hitting up a rock-climbing forum board is usually full of good ideas.
Lifting gloves with a traction grip are fine, the muscles utilized in grip are still being trained, but I'm not a big fan of the wrist strap idea (but then again, I don't care much for lifting belts either). Those items, with the exception of their use during ultra-heavy power and Olympic lifts, are really nothing more than a crutch, and don't promote strengthening of the entire kinetic chain. And given the fact that pull-ups are a functional exercise, and you are already experiencing an abnormal pain at some link of the kinetic chain during the exercise, then you should be addressing the weak link in the chain, not covering it up with a wrist strap.