Everyone has a different butt shape & your weight has little to do with the discomfort. This topic is covered fairly frequently so a search will give you more info.
- Coasting is bad. If you are constantly pedaling then your weight is on your legs and arms and not 100% on your butt. Road bikes & their saddles are not meant for "sitting", they are there to keep the frame between your legs and provide another anchor point (hands and feet are the others). Sitting on a road saddle will result in a sore butt.
- A notched saddle (cut out) can help with taint pressure & rubbing
- Saddle width is critical. Dealers who sell Specialized BG saddles have an instrument for measuring sit bone spacing. This will let you know how wide a saddle you should try (a starting point, not a final answer).
- Correct saddle height, tilt, and forward/rear placement is critical