Thigh pain, training for marathon

[mumof4]

Hi,
I'm training for my first marathon & averaging 3-4 runs a week, 8 miles each run. I've now got a really painful left thigh, started as niggle behind my knee then travelled up my hamstring and is now right at the top of my thigh and feels painful deep inside my leg. Took 2 weeks rest and tried stretching it out loads and leg felt loads better but went for a small jog today, 3 miles and pain is back with a vengence. Any suggestions to what it could be? I know I probably need to see a sports physio, got appointment in 2weeks. Worried that my fitness/training plan is now going awry.
Many thanks

[Heidi]

Hi
When you say thigh do you mean the back of the thigh all the time?
Is there a point that you can touch which is tender?
If not, then I would suspect the sciatic nerve referring pain into the hamstrings. This can be caused by lower back problems, although as you haven't mentioned any back pain, my main thought is piriformis:
http://www.sportsinjuryclinic.net/cybertherapist/back/buttocks/piriformis.htm
Definately go to the sports physio, but in the meantime, try some glute stretches too (you can find them on these pages)

[aaliya]

Do you really think that this can be covered up??? I am really confuse about this..