I was referred to physio just as a precaution really when marathon training,was told I had patella femoral syndrome caused by under developed muscle on one side and over developed muscle on the other side of the knee cap causing it to be slightly out of position. AKA runners knee,was given some exercises to do such as leg raises,calf stretching and some resistance band exercises,apparently my really tight hamstrings weren't helping,but tbh it seemed to sort itself out. The physio did say it was at a really early stage but seemed able to diagnose it straight away. I went to my GP,was referred to physio and was seen within a month,all on the NHS.