Sometimes the ideas for stories come from the most random places. For the novel (my first) I'm working on right now it came from power rangers, though it has nothing to do with power rangers. One of my friend's on Facebook posted a status about things that kids who grew up in the 90s would know, that are no longer really around. One of the things was power rangers.
It got me reminiscing about power rangers (which when I was younger I was OBSESSED with) and my favorite Rangers from then, which was always the
6th power ranger. The sixth ranger was a guy who wasn't part of the main team of rangers who came in and played an important part, but wasn't as important as the Red Ranger. Often times there was some trouble in their life that kept them from being a ranger till then.
Specifically, the inspiration for the my MC was my favorite ranger of all time - the Titanium Ranger,
Ryan Mitchel (though I named my main character after my second favorite the Silver Ranger Zane who was in a coma for 2 years and wasn't able to be a ranger for that time)- who had a traumatic experience when he was young and taken from his family. When he returned he had trouble fitting in and felt like he didn't belong. Also I had over my life had a series of power rangers related dreams. They were all very similar, I was the sixth ranger and it was between ranger teams (the old team of rangers was retiring and a new one coming in) and I was trying to fit in with the new team. It then clicked that the MC's motivation is trying to find some place to belong and not be alone anymore.
So I had a main character and what motivated him, but I didn't have a story yet. So then I thought about what I liked and knew that i could write about. I had gotten into Star Trek Recently (following my family tradition of being a Trekkie, my brother even collected the trading cards) and from the start it would be a SciFi novel.
So I had a genre and a main characters motivation, plus what general kind of role he'd play, but those things by themselves don't equal a story. So I looked to what I liked and thing I had knowledge of. i love history and politics, love reading about the military and spies, and my favorite authors are Tom Clancy and Vince Flynn. So I decided it was going to be spy novel/political thriller. Current events and history provided some themes, specifically the trouble with not heading warnings when they are given to us.
So I had all the makings of the story. I had what genre it would be (SciFi) and sub genres (political thriller/spy novel) I had a MC, motivated by trying to find his place in life and that provides the internal conflict for him. I had what kind of role he'd play in the action of the story, not a main player such as a general or president, but maybe an aide or something. I had the big external conflict, and I had a theme for it of ignoring warnings that are given to you. So I now have the foundation for the story and now I just have to put it together into a believable plot and fill in the rest.
Here's the advice I'd give to you think through your past. Is there something that happened that really caused made you who you are or were at one time, that you could turn into a story or a motivation for your MC? Or do you have a friend that has a personal story that you could work into a story? read history books, biographies, and memories. you might find something there that could inspire you. read psychology articles and books about what makes people tick and you could find something that sparks an idea.