First - Hope everything is better from your post yesterday.
Second - Because of what happened yesterday, I would take at least a week off from PE. Maybe 2 weeks.
You might be susceptible to re injury and or things may need some time to heal.
Third - Look at the videos Big Al has posted.
There are other places on the internet that may have info and videos.
Thunder's Place and PE Gym come to mind.
Fourth - When you resume PE. You don't want a lot of force. Slow stretches.
Nothing should hurt either during or after.
Work up to it.
Warm ups
Whatever you did 2 days ago was too much and you don't want to do that again.