These are great comments! No padded bike shorts, so I'm guessing I should invest. And I do feel like I am sitting a bit "off" on the bike, so I am going to get fitted very shortly. It feels like my seat is a bit high, so my lower back also gets a bit tired. And it's my butt that hurts after about 30 so I will keep in mind the comments about where I am sitting on the seat to see if that makes a difference.