painful ultrasound

Anybody else experience a painful ultrasound?? I had a trans-abdominal, 12 week/transnuchal testing and was shocked how much pressure was applied to my belly for majority of the test. With twins It took about 45 mins to measure both, and although thrilling to see them, we also had to take a break inbetween so I could rest! Apparently I was contracting from not relaxing! Wondering if anyone else experienced something similar? I'm fine now, just slept it off.