Muscle spasm in hamstring

[Harout_93]

My hamstring starts to spasm (painfully) every time I do squats, if I do really low weight then it doesn't, but adding any weight that i need in order to gain, it starts to painfully spasm. It didn't happen just because of one occasion, it happened every time, and I would always stretch and do warm up sets first. Even now as I sit here, if I flex my hamstring hard, I can feel it starting to spasm. So can someone please tell me what I can do or whats wrong?

[GridIron77]

Drink alot of water, drink gatorade, sodium, magnisum, stretch a crap load