I had that at 6 weeks too, only on my right side. It's exactly what cindy82 says, your body is just stretching and moving to accomodate your little one. Try some light stretches and lots of fluids, but stay away from got packs.
It's normal as long as your not bleeding and doubled over in cramps, it's your uterus stretching and body relaxing for baby. Make sure your staying hydrated and walking some helps