If they are lower in your abdomen could be contractions however if they are higher in your chest and back it may be gallstones. I have had gallstones since early on in my pregnancy and they have only bothered me a few times but when they do they HURT. The doctor wants to schedule to have my gallbladder removed after my daughter is born.
Sounds like contractions. If they are irregular, it's not true labor. If the become regular and have 6 with in an hour, call your Dr or go to L&D