Last week I was squatting and as I sunk into the squad my left quad went berserk like it had been electrocuted. It was as if I could feel each of the finest parts of the muscles fiber contracting and it was almost sickening. I squatted a bit lighter and it calmed down a lot but was still there. I also did leg extensions and lunges and could feel it slightly in there.

Anyway, today was legs and I did 10 mins on the bike felt good, went to the squat rack and it went crazy just like the week before. I did 2 reps of light weight and then stopped, didnt train legs any more.

Id like to know what it could be and what I should do.