have pain at high level of thigh near groin & spanning down a few inches

checked injuries & sounds like inflamation of abductor muscles but I am OK pulling knee up to chest, and bending foot up to grion but get real pain when I bend leg back, when trying a thigh stretch. I cannot get leg any more than 90 degree bend due to pain.

It wasn't an immediate injury had felt some twinge during training, but having tried a new sport one night (some new muscles used) I was stiff so I avoided my usual weight & fitness ruitine for a few days whilst the stiffness subsided.

The muscle pulled / or injury became severe when I was kneeling on the floor with leg at 90 degrees whilst, of all things, I was using my computer !

ironic?

I've stopped training (driving me mad) but any advice or guesses as to cause would be most appreciated, cheers