Pain on the outside of thigh.

Hiya,

On my new years eve run (8.5 miles) towards the end I developed a slight pain on the outside of my left thigh which went away within a couple of miles. When I tried running a couple of days after it was quite painful so could only manage 5. Nearly 4 weeks on the pain is still there and sometimes i can feel it in the front and tops of my thigh near the joint and down the shin but mostly its on the outside. I have tried stretching the quads and hip flexors and foam rolling with a tennis ball but it doesnt really seem to make much difference. 

Just thought I would try on here to see if anyone else has had a similar problem and any advice would be greatly appriciated! if not it looks like im off on a trip to the physio this half term

also one more thing, the left does feel slightly weaker than the right? not sure if this has anything to do with it?

Many thanks (sorry for such a long question)