I have bad pain in my knees when running, any suggestions?

See an orthopedist: The causes of knee pain while running are many. You may have damage to cartilage or a meniscus, chronic trauma to the joint, possible stress fracture etc. Se an orthopedist to make proper diagnosis. Measures may include simple use of orthotics or other supports, physical therapy, anti inflammatory drugs etc.

See Dr. or rest: You might want to quit running for awhile, rest and possibly take up cross training, incorporating swimming if possible. If the knee issue is chronic, i would get to an orthopedic dr. For a thorough evalaution.