k6mi, your best bet of getting your problem figured out is still going to be a doctor. If the dr you normally go to is not meeting your expectations, go find another that others may recommend as being "good". Your odds arent going to be good guessing what it is either, and it can cause to lose valuable training time, or injure yourself even worse in the event that it is actually serious. For the time being, rest, ice, foam roll it band, stretch quads, hip flexors, hams, etc. If it doesnt start to get better though youre still going to have to find SOMEONE to look at it, so I would start doing some research on a sports doc there or nearby.