Going very slowly throughout the ride, not trying too much on a beautiful Friday morning in Stow and Bolton and Harvard and Boxborough. Coming down Stow road in Boxborough I think my tire blew and caused a spill. I am very sore. I am very lucky that I didn't break anything. The cat scan at Emerson was negative. My initial soreness was my right but and my left groin. One day later, I am really sore in my groin and also I tweaked my back. Looks like I was going about 20 mph when the flat occurred, not too fast, I was checking to do a left turn onto Burroughs from Stow Road in Boxborough, about to take a left turn onto Burroughs Road. I did adjust my seat to lower it to the lowest possible height. That made it more comfortable on my right hip, but I could feel it more on my hamstring. But, my butt felt comfortable too. I think I need a little higher handlebar stem, I will ask Tomten Biketown for added spacers. And, I need new tires, and they need to check the gears, and the crank. My new seat got scratched and so did my right handlebar and hopefully my brakes are ok too. This was not a good route, too much on 117, don't do this again. Maybe I picked up a nail there?