I love my bike but since I've lost weight the seat has gotten increasingly uncomfortable. I presently just put a pillow under my tush but there has to be something better so I'm gonna look into gel seat covers to see if they have one that will work with my bike. I Hope so cause that would help alot when my sciatica acts up.
Bike seat comfort is all an individual preference thing. Different things work for different people - you just have to try and see what you like best. Some options are: gel seat cover, padded seat, padded shorts, a saddle that fits you better (which a bike shop can measure you for). The key with that last one is to get a saddle that's the right size so that your sit bones rest on the squishy parts of the seat.
My personal preference has been right sized saddle + shorts with a thin pad. But if you have trouble with sciatica, you may need something more.