Diagnosis of your knee cap pain will most likely be termed patellofemoral pain, and should be provided by a suitably qualified health professional. Other common terms include chondromalacia patellae and runners knee.
This infographic does not replace consultation with a physiotherapist or doctor, but it might help you to understand if you have knee cap pain (patellofemoral pain).
Some people believe that changes in structure (e.g. cartilage) of the knee joint is the cause of knee cap pain. However, research suggests no difference between people with knee cap pain and people without pain on MRI and X-ray. Therefore, imaging is not likely to help with knee cap pain diagnosis, or in determining appropriate treatments.
Crossley 2016. Patellofemoral pain consensus statement from the 4th International Patellofemoral Pain Research Retreat, Manchester. Part 1: Terminology, definitions, clinical examination, natural history, patellofemoral osteoarthritis and patient-reported outcome measures.