Why is it that people ask the dumbest questions when you need help or sympathy (or when you're not even speaking to them)?

Like if I walk into a room and say to my mother, my leg is really hurting and I don't know why. Then someone (not my mother) comes up with...Did you hit it, bump into something? Well if I had then I would know why it's hurting!!!

I just don't know why people a) Have to be all in the conversation b) ask stupid questions

Okay...rant over!

Have a good day!

~m