Stretching shouldn't be hard or feel painful. To produce the desired result of "down regulating" or "increasing flexibility" you can't stretch to the max.
Stretching is the process of stimulating your golgi tendon to produce a "relax" signal, overzealous stretching changes that signal production creating a different response.
Use a 5/10 discomfort level while stretching, anything more intense than 5/10 wont be producing the desired result.
Research also shows that if you want to see the desired result from static stretches you must be completing them daily and holding for 180+ seconds at a time.
Yours in health,