Hi, I've been running for a year and a half on and off. Since September I have got quite into it and have built myself up to comfortably run 6 miles. Have just entered myself for my first ever 10k race. I wanted to improve my speed so went to a session that practised sprinting. I really enjoyed it and with being shown how to get the best result was running quite fast in short bursts. Problem is now, that 10 days later and I am in so much pain across my quadriceps. Was a bit achy initially after but thought was normal as obviously using muscles differently to normal, but even now if I kneel on the floor and try to stand up it causes a tearing sensation that is very painful across the top of both my thighs. I tried to have a little race with my son earlier and it happened again. I'm so frustrated but can't even try to run. Has anyone else ever had this, will it take long to get better? Do I need to see a doctor or will he just say I've sprained my quadriceps?