All I can say is "ouch." Some awful
Both of my most painful experiences have been bicycle related. When I was about eight, I was riding my bike past the local shopping mall when I saw what looked like a dirt path that went off into the woods behind the mall. Curious, I decided to ride my bike down that path and see where it went. Unfortunately, the "path" ended at the top of a wall behind the mall's Dumpsters. I couldn't stop the bike in time and went flying off the top of the wall, fell about six feet, and landed on the side of my face. (I suppose I was lucky I didn't crash directly into one of the dumpsters, or I might not even be here today!) Like an idiot, I got back up and rode my bike back home through a haze of blood and pain (fortunately it was a short ride), and I remember my poor Dad was in the front yard doing yard work when I came screaming up the driveway, he took one look at me and nearly had a heart attack, my face and clothes were covered in blood and dirt and I must've looked like an outtake from a zombie movie. Long story short, it took several hours in the emergency room for the docs to clean all the dirt, grit and gravel out of my face and several stitches at the corner of my mouth to close where I'd ripped my lip.
Years later, I'd upgraded to a ten speed bike, and was riding it down a particularly steep hill on my way to go play some video games at a friend's house. I reach the bottom of the hill, try to slow down at the bottom... brakes don't work. In a panic, I look up - telephone pole. BLAM
! Smack into it head on and hit the ground. My brother, who was riding in front of me, kept right on going and had no idea anything had happened till he turned around to say something to me and I wasn't there! He turned around and found me in a heap on the ground bleeding from my knee and a gash on my head. That got me my first ride in an ambulance and six more stitches in my knee. I haven't been on a bicycle since then.
Oh, and about two weeks ago I fell off the roof of my RV trailer while I was covering it up with a tarp for the winter. I attached the tarp to the front of the trailer, hopped up onto the roof from the rear, pulled it all the way to the back, and was going to jump back down to the ground by climbing off the roof onto the attached spare tire. Well, I missed the spare and went crashing all the way to the ground. I still have some bruising on my chest and my arms. The pain wasn't too bad, but the nagging from the wife which is still going on ('next time wait for me to bring you the ladder dammit, you could've broken your neck!' etc.) is unbearable.