Last week I went on a hen weekend, done some walking, then out at night in my heels. I didn t fall over or bash my knee at all, and don t remember pulling any muscles etc but late at night when I was coming out of the club I noticed my knee was hurting (never had this happen before) The next day it was still sore and the only way I can describe it was it was like my knee needed an oil. I wasn t doubled over in pain and have been fine to walk, just felt sore. This was a week ago now, and the pain is so much better, although it does hurt when I kneel down to play with my daughter, but I have noticed an egg size lump forming on my right knee cap. What could this be?