I see no one mention sitting on your sitting bones. People have a tendency to collapse their spine at the base, and then rotate their pelvis backwards to slouch, even if their upper body is straight.

If you sit aligned you can feel the bony part of your butt touch the seat, which although uncomfortable at first, makes sitting longer more tolerable after time.

At university we would have a lot of classes without chairs, so we’d sit on the floor a lot, and the above would help.

Be young. Young folk never sore

The true bleachers experience is all about getting burnt/frozen when sitting down, then having to endure the pain of zero padding for however long you have the displeasure of sitting there.

There is nothing you can do, bleachers are designed for maximum cheapness without posing a huge safety liability, and have zero dollars put into comfort during development. Literally minmaxed to optimize for cost.

There are bleacher seats with back support, but they are cumbersome to carry and if you stand up, you can knock them onto the people behind you. Also, they’re a bit anti-social in a sold out event where everyone’s squeezed in.

I’ve found inflatable bleacher cushions to be a good option. Some store very small in a pouch, then you blow them up at the game. If you tip them off the seat, nobody gets hurt. No back support, but they make sitting a lot more comfortable.

You shouldn’t have pain just from sitting. Doing yoga or pilates or other strength exercises can stop this from happening.

It’s a function of your skeletal muscle system. Most people are underdeveloped because of a sedentary lifestyle, or jobs that keep them sitting all day.

You can try to develop these muscles slowly over time, YouTube has a lot of different strategies.

When you’re in the stadium, be dynamic, change postures, if you can do an Asian style squat on the seat.

At the office, try using a stool instead of a chair, or try standing desk. Try to move up the time that you can be dynamic. Bonus points if you get a balance board. Those are great for building that core muscle strength. But it can be tiring so go slow

I think this is a case of weak muscles. Don’t get me wrong it doesn’t surprise me given how many people sit on chairs and couches all day. But yeah. Start with air squats.