On Monday I hurt my knee. Didn't pull or twist it, it just became stiff and uncomfortable. When I woke up Tuesday morning it was very painful so I went to the local walk in centre where a student doctor diagnosed muscle strain. Rested it as much as possible for the next couple of days. However yesterday we went for a day out which included quite a lot of walking and stairs. By the end of the day I was in agony, close to tears. Worried it may be more than a strain. still very sore this morning. Any ideas or advice please. Would love to be up and running as soon as possible.