My dog gave me motivation to run everyday when he was still alive. Because of his breed, shiba inu, he could run for days without stopping. Despite his old age at 18m he was still running ahead of me even at 4 miles. 5 years have gone by and his little dirt path ring in the backyard is still back there. I'm going to get another Shiba when I get a job because it's much more fun running with a companion. For now though I just pick a point, like a light post, and run to it. Then I pick another light post/tree/building and run to it, takes the attention off your legs.
Ok so this might sound stupid and a little weird but some people really like it. If you look up "Military running cadence" online you can find lots of cadences that are made to sing WHILE running.
I hate running to be honest but I'm very good at it now and I find it way more enjoyable when I do sing cadences. It's even more motivating with more people (I have the benefit of running with my platoon and company where we usually do cadences).
So look some stuff up, some cadences are silly, some are gorey, some tell a really awesome story.
Also the cadences are sang in a way to help you control your breathing usually.
I personally like imaging that I'm in a fandom of mine to motivate me to run. Example, I pretend I'm the Doctor's companion and we're being chased by Weeping Angels! XD If I'm not in the mood for that, I default to blood pumping music. Terrible as this may sound to people who can't stand today's boy's bands, "Elevate" by Big Time Rush is SUPER motivational. Very fun and energetic! And their constantly saying, "Elevate" in my ear buds is like a personal challenge to step up my game. ;P
"Music" by Manic Drive is a pretty kick a** song, as well (and if you're an aspiring musician who is absolutely passionate about, you might enjoy that song, also).