Fussy,
I'm probably the last person here who can give you advice about this. I don't have children and have never been married. However, I do have family members with this type of "get over it" attitude. So, I'm willing to try to help.
First of all, your son is 14-you're right, that's bad enough, LOL. But, he is obviously getting this attitude from his father (in my opinion). I don't know what your relationship is like with your ex, but if it's strained, I'm sure this negative attitude isn't just about the fibro.
I grew up with a father who convinced me that I should never show any emotion-crying was not an option-and when I was sick, I needed to just "suck it up." This made me very resentful and our relationship was strained for years.
Is there anyone in your family (besides his dad), that can sit him down and explain things to him? Obviously, he doesn't understand what fibro can do to you, and the horrible pain and frustration you go through on a daily basis. Also, he may be in denial, or just going through his own growing pains of being a 14 year old boy. What I mean is, he may have his own issues to deal with. Again, I don't know all the details about your relationship with your ex, but it sounds like no one is on the same page. It also sounds like your son is resentful towards you about something. Would it be possible to talk to your ex and explain to him how your son is acting?
Anyway, I really don't feel like I've given you any advice, but I hope that something I said has helped. If anything, you can always come here and vent, and maybe those with children have some better suggestions. I really do wish you well.