Thanks so much for your very informative response.
I have already started the exercises as you have suggested and I noticed in my left side on the first exercise that there was some discomfort which to me says there is something obviously not right in that area. (Left side is the issue). I didn't feel the same with the right side.
Started 2 weeks ago towards the end of a long run. Came on without warning and forced me to stop as it felt uncomfortable. Basically first felt at the back of the leg and it was hard to pinpoint but it caused me to limp the rest of the way and the day after. Been to physio. Told it was Itb. The pain that I was feeling at the side of the knee to touch has subsided but when I tried to run earlier this week I managed a mile before i felt it start coming on again. Felt the pain on bending the knee (as if I was bringing the knee up towards me) and also felt when kicking the covers off me in bed. Have been strengthening glutes and rolling daily. Also been swimming and cycling to get me out the doldrums. Anybody else had this?