Could be ligament pain, your ligaments will be starting to stretch now probably. It's called round ligament pain, although generally it starts about 14-16 weeks I had it start about 12 weeks this time. Can't really remember with my first but I think it started about 13 weeks with her. I actually called my midwife because I was so worried when I had my first but she assured me it was just stretching pain. If it's persistent it needs to be checked though.