I am having pain in my left upper leg. it feels like i pulled a muscle. could this be a blood clot?

Unlikely: No one can rule out a blood clot based on this brief history alone, but the majority of blood clots cause pain in the lower leg, particularly the calf region. Signs include swelling, redness, increased warmth, fever and distention of the veins. Risk factors include recent trauma or surgery, prolonged immobilization, recent lengthy travel, smoking, use of birth control pills and + family history.