An X-ray can only show the bones. It cannot show injuries to the cartilage, meniscus (knee cushion), ligaments, or other soft tissues. If the pain is persistent, especially while walking, climbing stairs, squatting, or if there is swelling, locking, or a feeling that the knee is giving way, an MRI may be needed for further evaluation. For now, I would advise an orthopaedic consultation, knee-strengthening exercises under the guidance of a physiotherapist, avoiding excessive strain on the knee, and using pain medication only as advised by a doctor. Maintaining a healthy weight can also help reduce stress on the knee joint.