Hello, and welcome to HCM!
It sounds like you have "pulled a muscle". This means that you stretched the muscle further than it should have gone, and it is now torn. The good news is that usually this is not a tear that goes all the way through the muscle, and can heal on it's own. Having said that, it would be wise for you to be evaluated by your family doctor, since the pain is so severe. Physical therapy
may be helpful in shortening the time needed to heal.
I wish you good health, and thank you for posting on HCM!