Did you see 気を病む somewhere? I would have to imagine 心配する is orders of magnitude more common. I know it's something that could be said, but I've lived in Japan for 4 years and I've never heard anyone use 気を病む.
I'm sorry this is so late, the context is I was reading Bleach and was trying to figure out what the difference was. In volume six Rukia says: 気に病むな 貴様の せいではない. Ichigo replies with : あんあ もん 心配する ほど の けが じゃねーよ！Then she says: 誰が 心配してる と 言った？ 私 は 気に病むな と 言ったのだぞ
I went back and looked up 心配 and saw that it can also mean to care about someone with the second definition, so I think the idea was she was trying trick him and say 心配する as in caring about someone rather than general worrying.
Here's a link to the page if you want it. https://rawmanga.top/Bleach/VOLUME_006/154
Well I'm not completely sure, but after looking through Japanese dictionaries for a bit, every example sentence I've come across uses 気に病む to mean to worry about something trivial; to worry unnecessarily. If this is really what it means then yes there is quite a difference between that and 心配する. When Rukia uses 気に病む, she is teasing Ichigo for worrying so much about something so unimportant, after which Ichigo uses 心配する to mean that that thing he's worrying about is a legitimate cause for concern. As Leebo said, 気に病む is quite an uncommon expression, I think most people in real life would instead say 気にする which pretty much means the same thing.
What's the difference?
What's the difference between 心配する and 気に病む if any? They both mean to worry but is there any significant difference? Or is it just like with the English words 'worry' versus 'concern' they both mean the same thing just different spellings.