Takes a few weeks for your butt to get used to riding. If you are new to riding or haven't ridden in quite a while then it can be quite the pain for some of us.
If your pain is just something you feel in the bones or joints of your pelvis, then just bear with it and keep riding. Once you get past the pain part and over it, then you can try out different saddles if needed for better comfort. Otherwise, the saddles you get while in the painful phase of getting use to riding won't be the correct saddles to have.
If it is an actual sore or skin irritation, then something else needs to be done for that.