Its definately round ligament pain! I also get it and spoke to my midwife aswell as GP about it. You may also get it when you roll over in bed, sit or stand, oh and coughing!
Nothing to worry about, just your uterus stretching!
GP told me to hold your stomach in when you cough or sneeze so the ligaments don't stretch as much just as hudsy has said.
I'm at the point where I get pains my hips now lol. this is also another form of stretching.
I was up last night googling the same thing!! I'm having terrible allergies and sneezing about 20 times a day and every time I get shooting pains! Like texasangel said, best relief is leaning forward holding your stomach so the ligaments aren't stretching any further. The worst is lying on your back when you sneeze..ouch!
It's probably your round ligament (the lower front part of your uterus). Mine hurts to. I suggest leaning over forward and/or holding your stomach when you sneeze or cough.