Pains sometimes on left side and sometimes right side

Hello ladies i had my 1st ob appointment yesterday at 12 weeks and well i had no ultrasound done nor heart beat so im very sad. Doctor said maybe next week i can hear heart beat but no ultrasound until 20 weeks. Well i been getting sharp pains (not too painful just uncomfortable) sometimes on my left side and sometimes the right side. Has anyone experience these pains and know what they might be ? I told my doctor but still doesnt want to do ultrasound until 20 weeks /: