Thank you so much Carnkin for your efforts to provide me with such useful info. Although, for now, I've stopped going to the classes because of the pain but as soon as I resume my classes, I'll keep these things in my mind.
I was researching about all this and I wanted to know which part I actually got damaged and I found out there is a muscle named Quadriceps Femoris which lies just above the knee and I'm quite sure that is where I can feel the pain. Now the question is, shall I consult a dcotor or is there some home remedy that can help me get rid of this completely.