Butt Its Sore
YES!! I understand this problem well. I have owned Yamas/Hondas and ridden Harleys at times so, it is not always maker specific. It is however, usually model specific. I am a 6'1" big boy so the weight of my world is centered on that area and pushes down rather heftily.
Solutions as mentioned may be different for each person. I have seen/tried solutions from taking your seat apart and re-cutting the foam for a different fit, having a seat maker do that, taking the seat apart and installing a "gel" pad or, putting a gel pad directly on top the seat, to buying a replacement seat entirely.
The most direct solution is to buy another seat also most costly and you better know the return policy.
The big problem is you can't really tell until you have driven down the road for a while before the pain starts. So, unless you are doing some of this yourself, it can get expensive very fast. I have had the Mustang seats, and they are good, I have had the Corbin seats and they are great. I have tried the gel pads too but, did not find, for me, a good solution there.
Keep reading on the internet and doing searches on your specific bike and that pain seat issue and you might run across a home-made solution. Other than that, maybe look at return policies, or buy used seats on ebay/craigslist if you can find them for your model bike.
Good luck and hope it all works out for the end. Yeah, I thot I wuz phunny!!!