thank heavens you're OK....trucks and chairs can be replaced...you can't.
Sounds like you'll be in the dog house for a few days - with a big bottle of aspirin.
Hope the sore muscles heal quickly.

But I will add....whoaaaa, thanks for the pictures. I always get a little nervous following a vehicle with a motorized chair mounted on the back. I've always wondered what would happen if the chair came off - now I know (I'll never follow behind one again).
Years ago I hit a couch that came off the back of the pickup truck ahead of me (gentleman was hauling it to the dump). Thank heavens it was 75% trashed already when it fell and the couch basically exploded when it hit the pavement. Besides a broken headlight, cracked grill (and the fact that I needed clean undies ) I came out unscathed.
Happy to hear you'll be OK.