Originally Posted by
MichaelW
You are riding too far too soon. Ride by time, not distance. Start with maybe a 10minute ride and extend by about 5 mins each time. Don't ride too hard, you need to become conditioned to riding before you use it for fitness. Take a week or two just to settle into the bike.
+1
In addition to the comments about fit, this one is key. While you are adjusting to the bike, and adjusting it to you, you need to limit your riding time to that which you can accomplish with most of the load on your legs, not "sitting" on the saddle, so much as "perching" These days i only have sore ass syndrome when very tired and slump on the saddle like a sack of spuds. If you can borrow to try any cheap ass saddle that is wider than what you already have, that might help too, not more padding, just wider at the sit bones.