My right hip and knee has been hurting for 3 months. no injuries, x-ray found nothing unusual. it hurts sometimes when and after i run. what's wrong?

Hip to knee pain: Radiating pain from groin (hip) to knee suggests one of two likely possibilities. 1) there is a hip problem—hip joint, torn joint cartilage, collapse of bone, or congenital problem—which would be visible on xrays or mri. 2) spine problem—herniated disc or pinched nerve affecting the higher lumbar levels (l2-3-4) causing front of thigh symptoms—mri would show. See your doc. Too much pain too long.