tight muscle

Good Morning, I would like to know how to stretch out the quad muscle. I did lunges,Around the Clock, 5 days ago. My left quad is tight still, I have tried stretch it by holding my angle and raisng it backward. After stretching last night I did about 20 walking lunges again my left quad because very tight, felt as if it would tear. After rubbing it I found it raised it like a knot. Am I not stretching it anought or could it be a muscle cramp that I can’t shake.

you need to have a medical expert look at your leg, In the meantime, stop lunging!