If you run outside, chances are high that you have encountered some hills. Hill work is considered one of the building blocks of running because it builds strength. So don't avoid the challenge of the natural incline.
When running uphill, it helps to follow the biking strategy. Cyclists prepare for their climb by shifting into an easy gear for the ascent. Runners should switch gears too. Instead of trying to attack a hill maintaining the same pace as you would on flat terrain, slow down. Your energy output while running uphill should remain the same as it was before you started your ascent. Your breathing should not speed up and your heart rate shouldn't either. While you might be moving more slowly, you're using your energy more efficiently, so you can keep on running, which really is the point.
When I am running uphill, my mantra is "slow and steady wins the race." I may be a tortoise, but I am still running.