So many factors can lead to a huuurting bum. It is not easy for strangers to diagnose the problem without having seen your bicycle, and you riding it. For all we know, the problem is caused by a seat that is too wide, too narrow, tilted up, or tilted down. Your clothing might contribute to the problem, or it could be related to your personal hygiene, the dimensions of your frame, the height of your handlebars, or your riding style.

My suggestion: Go to a good bicycle store, and find somebody who understands bicycle fit. The person should observe you, your bicycle, and your riding style.

One of my riding companions had a case of a huuurt bum, and discovered, from consulting with a good bike mechanic, that the source of the problem was the size of the frame. It was way too small, and no change of saddle or adjustments to same was going to make a significant difference.