Are there certain places that are more painful?
In general, the more muscle or cushion you have the less it will hurt with the exception of really sensitive skin areas (underside of your arm, inner thigh, etc.).
I have 3 tat's currently. My first is around my left ankle and was a 3 hour, toe-curling ordeal as the ankle is nothing but bone, nerve and tendon.
My second was on my right calf. It took an hour and actually tickled more than hurt.
My most recent was my backpiece. It was 3 hours and medium high on the pain threshold.