Go to a bike shop that has a device or some way of measuring your sit bones (ie. the distance between them.) They’re the two hard bits that should be contacting your saddle when you ride. The shop I went to had this bench with a gel layer so you could see where your sit bones were pressing down.

I used to think all saddles were uncomfortable until I realized I have a relatively wide distance between my sit bones. I bought a proper saddle for my ass and now I’m comfy all the time.