Serious pain in left hamstring after squats

[MrMonster]

I just hit the gym, first session in about 2 months after an injury and I got one set of squats done and when I went down for the first rep of the second set I felt an agonising pain that almost made me drop the bar in my left hamstring..

I warmed up properly, I stretched and done a warm up set with 50% of the weight I used.. I didn't go high because my squats are apauling anyway..

Anyone know what this is? It's the same reason I had to stop squatting last time and it's really beginning to bug me because squats are one of the main lifts of almost any program. I even tried the leg press to attempt to finish it off but it still was painful. Just got home and walking up the stairs even brought the pain back..


Ideas on what it is and how I can alleviate it a little? Really pissed off atm.. :S