If the seat is adjusted correctly and it still bothers you, it could be many things. Have you tried a good pair of cycling shorts? These include padding and they’re worn without underwear so that there are no seams and only comfortable padding inside between you and the seat. Another possibility is that you haven’t conditioned your butt to riding. It usually takes a few weeks of regular riding to get used to sitting on a bike seat. If these steps fail, it’s probably a bad seat. Visit a shop and try other seat designs until you find one that feels great. Gel seats are very popular but there are plenty of designs to try.