A break...I dunno..do they hurt at all when you now aren't knitting or is it only when you are actually knitting? If it's only when you're knitting then I'd say you can start anytime.
You can go to a yarn store and see if they have needles you can try before you buy. However you can also by a sampler set which has 3 sets with different needle materials to test.
This is the brands KH will be selling. It also has one of the Cubix which I've heard is easier on the hands.
This is the set from Knitpicks and it also includes 3 sets of needles of different materials.
I don't know your financial situation, but if you're going to knit either one will be something you'll use forever.
And if you decide to go with interchangeable circs do yourself a favor and get some grippy shelf liner and cut a piece off to carry in your needle/notions bag. It helps to tighten the needles on so they don't slip. This type of stuff-