Sharp sooting pain in left leg from back thigh to back knee could it be another blood clot theres is no swollen leg?

Unusual : 30' s female w. Pain in sciatic region of thigh asks whether is blood clot. This is unusual region for blood clot. If is blood clot would expect swelling of leg ; pain elicited by direct pressure on region ; when tense leg flexor muscles against resistance. That said, these sympmptoms in someone who already had leg blood clot causes all bets off, and doctor and ultrasound are probably indicated.

Possibly: You mentioned another blood clot, I am assuming you've had one before? If so, it is possible that you've had another one. Secondly, could be stretched hamstring or muscle strain. Lastly, if all is negative then consider a spine issue as a possibility that may need further evaluation.