Cheers guys, yeah it hurts more behind the knee especially after sitting for a while or getting out of the car and trying to walk but the pain also shoots up the middle of the back of the leg. I have been stretching as suggested but was unsure how much to do as I heard too much stretching could make it worse and I do Pilates but just once a week. I am also doing other exercises which I believe should help Gluteus Maximus recruitment but need to review this as there might be better exercises I could do. Tried cycling which felt fine whilst cycling but I was very sore days after, similar to the short runs. I guess just need to be patient(which is very difficult

) and take it slowly by the sounds of it