In the article you're reading the woman is saying that she was an educated, well employed woman who ended her career to raise her children. That made her brain hurt, figuratively. In other words, she felt dumb because she was no longer challenging herself in a work environment. Her children have now grown & she is able to get back into a work environment and accomplish things outside of the house. So her "smartache" is cured, gone. But yes, it's a made up word & I had to read the article to get the context of what she meant. There are better ways to say what she was trying to say.

Hahaha, this is a made up word. It doesn't yet exist in English. However, since it is a play on other types of ache, the meaning is easy to understand. Words that exist are "headache", "back ache", "stomach ache", so "smartache" means that the writer's intelligence (being smart) hurts (aches). Probably they are trying to say they only speak to stupid people, and it hurts their brain to think like a stupid person.