Why is life such a sh$% for some people

Hi all to jump straight in. My missus broke her back 2 yrs ago, ok you all say she's lucky she can still walk (although she is always in pain) it's taken me 16 yrs to convince her to marry me (mainly due to how i looked after her after the incident) (11 augustis the lucky day)she is the kindest person you will ever meet and would give you her last penny or help in any way she can. Yesterday she was trying on a new t shirt she bought and the tag hit her in the eye, so what you may say but she was in agony I drove her to the Dr and it turns out she's scratched her cornea, the Dr gave her drops and they actually seem to make it worse. Why is it that a kind and caring person has to suffer for some stupid reason, I've broken bones (doing stupid things that benefited none) Pam only does kind things and always puts others before herself. We sit here telly off lights off as they hurt her eyes if they're on i get the sence she would scratch her eyes out they are so painful. I don't understand, I would willingly take the pain, and worse, what I don't understand is why Pam, she is kind has only ever been the same. I was not like that in my youth I hated bullies and went out of my way to deal with them, Pam has not a bad word for anyone and only sees the best in people why is it fate seems to only deal her the crap hand.