Hello I am a 57 year old Male, reasonably active but a bit overweight ( 240 lbs, 5 -11 ) 3 years ago I had a heart attack which was treated with a stint. This evening, about 3-4 hours ago I noticed a dull ache in my left leg, just below the knee. The pain has gotten increasingly stronger and persistent. No impact or injury in recent days, no strain or twist just an increasingly dull throbbing ache which is not relieved by changing position or elevating the leg. Is it possible this is some sort of blood clot or something more severe?