We all know that every hero needs an adversary - the "anti-hero". That pretty much goes without saying. But there's more to tension and a good story than the good guy vs. the bad guy slugging it out. There are all those other characters - sort of like the family members you might like to forget.
Think about all the books you've read and for that matter, the movie's you've seen. There are all sorts of things going on in the background that add zest to the story and there's usually that character, a good-guy character, who drives your hero or heroine nuts, inadvertently puts obstacles in his or her path, pushes their buttons, and is generally a pain for the hero/heroine to deal with, yet can be a best friend, a close relative, a meddling co-worker or any other of a thousand possibilities.
This isn't the villain, the bad-guy character, but might be a side-kick or perhaps even simply a thickheaded character as in someone in authority above the hero who cannot be convinced to the hero's cause and ends up being deliberately obstructive.
Some examples of more prickly characters to torment your hero might be a superior police officer who takes the hero off the case. Or it could be a senior reporter who won't pass along story details because he or she doesn't want the junior reporter to get the credit for a story or in politics it might be an elected official who stops an investigation that would put the folks who bought and paid for him in jeopardy. These aren't the hero's buddies, but they aren't the villain (though they can be nasty) and they most certainly serve the same purpose - distraction, tension, obstacles.
Or, if it's not a character deliberately trying to side-track the hero as in the above paragraph, it might be a friend who's always in the wrong place at the wrong time putting him or herself in jeopardy or working at cross-purposes with the hero's intent, meaning no harm, but serving his or her own purpose. Writing these characters into your novel can create all kinds of interesting problems complicating the story by throwing up all sorts of roadblocks to the hero's progress. It can create amusing an/or deadly situations.
Whichever way you want to go, whether an overbearing authority figure throwing in 'monkey wrenches' or a more 'loveable side-kick" type remember when you begin to develop the character, it needs to be one in a position to annoy, get in the way, thwart and generally be a royal pain. With that kind of a character in the story, a sort of friendly adversary, your hero gr heroin will get plenty of chances to struggle, verbally spar and generally showcase his or her ingenuity and the stuff from which he or she is made.
Oh, and remember when writing your story, don't allow room for character confusion regarding your lesser characters. Take things as they come, don't try to throw too many characters at your reader at once. Don't refer to one character by several different names and when introducing a character for the first time give the reader his or her whole name. Then writing can proceed with just calling that character by one name, the one you stick with all the time.
Got the basics? Okay then, go out there and torment your hero!