Um, I mean that sucks that you have a fucked up shoulder, but I seriously doubt anyone can find any solace in feeling bad for you... and if they could, why would you want them to?
I have a very high sense of humour, I understood the joke, didn't find it funny.
Maybe if something else was wrong instead of problems with controlling your shoulder.
You might want to go deeper into the odds of what people least have, or something is that is funnily insulting.
"You can't sleep after you got back from work and you feel exhausted? I have orange eyebrows, how do you think I feel!"