You need to find your own reasons to run. There are many obvious reasons, health benefits, weight loss etc but only you can decide, because if you dont have a good reason to run you won't stick with it. If it's for the aforementioned reasons, they are not enough, any form of exercise will accomplish that. and maybe thats what you need, a variety, and running can be part of it. Running, especially competitive running, needs some other motivating factors. You can run recreationally to meet new people and exercise. You can race for new challenges and a sense of accomplishment (and charity reasons). It should be an inner drive reason.
Personally I run because I love running on city streets. I love the challenge of pushing myself and finding out how far I can go. It's also a form of stress relief and I enjoy the runner's high afterwards.
In running you are ultimately dependent only on yourself. It is your own discipline that makes you run, and that provides the benefits you reap. Running will increase your pride in yourself, and improve your relationship with your body. You will surprise yourself with your capabilities and reserves, achieve more than you thought possible.
Running gives you time to yourself. Even running with others you are essentially alone. You will be more in contact with the world around you, in all weathers and all lights, and more with yourself. Running gives you a space to yourself, a time to think, to muse, an active form of meditation. I originally started running for health reasons, I now run for all of the aforementioned reasons.
Running is the classical road to self-consciousness, self-awareness and self-reliance. Independence is the outstanding characteristic of the runner. I'm learning the harsh reality of my physical and mental limitations when I run. I've learned that personal commitment, sacrifice and determination are one of my means to betterment. I get my promotion through self-conquest.