Stretching/pain

Kilie • 22 years old,married I have a beautiful daughter and pregnant with baby#2 in Cali from wyoming.
This is my second pregnancy I'm almost 12 weeks and  Every once in a while I arch my back backwards when I stand up to stretch I will feel a tight, stretching pain in my uterine/lower abdominal area today I arched my back backward and felt such a horrible, tight, stretching pain in my uterine area that I had to double over in pain until my muscles relaxed again. Anyone else have this?