Yesterday i was doing my workout and after my last set (I do 5 x 5), i felt a sharp pain developing in my right hamstring. It wasn't too painful but it was definitely noticeable. I noticed my knees buckled in (by accident) slightly during one of the reps. Could that be why my hamstring hurt?
The pain was gone by this morning. Should i continue with my squats and deadlifts on Monday?
Also, is your lower back meant to be staight or curved during squats? I just stick my butt out and my lower back stays quite straight throughout the squat.
What routine are you on? I found my hamstrings were comparatively weak after doing a squat-based program for a while. I pulled a hamstring doing front squats and it took almost a month to fully recover. I've now added hyperexentions and GHRs to my routine and my hamstrings feel a lot stronger.
Squat based programs are good for a while, but once you get to a certain level, a bit more hamstring work is needed to keep everything in balance. This is what I have found from my experience.