Running isn't bad for your knees and doesn't cause arthritis.
Running isn't bad for your hips and knees.
“The principal finding in this study is that, in general, running is not associated with osteoarthritis,” Dr. Eduard Alentorn-Geli, of the Department of Orthopedic Surgery at the Mayo Clinic, said in a press release. “The novel finding in our investigation is the increased association between running and arthritis in competitive, but not in recreational, runners.”
This is belief is often held when people have knee pain with running or are new to running and aren't quite sure what they are getting themselves into. There are a lot of reasons someone can have knee pain and for each cause, there are different solutions.
More popular among runners will be to turn to getting better shoes, orthotics, stretching, foam rolling, hip strengthening and single leg balance exercises. Some of these solutions cause dependency becoming a crutch you will always need for running, while with others are a basic shotgun approach based on large population studies that don't address an individual's needs. Can these things help relieve and manage some pain? Yes...and no. They can help to improve the overall condition/health of the soft tissue, but often aren't enough to address a biomechanics issue that is causing the soft tissue injury in the first place.
I'm a runner myself and I know its no fun being injured and hate having pain while doing it. I love working with runners to figure out a plan to help them keep doing what they enjoy and can be a part of their healthy lifestyle.