I have knee, hip, and back issues compounded by my (self-adjusted) bow-leggedness, flat feet, overpronation, and bad gait. The more I research and hear from people, the more I'm hearing "holy crap get a gait analysis and orthotics."
ETA: What will my race time be for my 5k race tomorrow? I ran my first one 3 weeks ago in 29:10. Closest answer gets a crappy gift of my choosing or a month of paid time.