One sided pain!

I'm 6 weeks and 5 days and today have been having a strange feeling by my hip bone on the left side only. It feels like a pinching/tweaking sensation. I had an early ultrasound at 6 weeks, so I know it's not an ectopic pregnancy and everything was fine. Anyone else ever get anything like this? I'm not worried enough to go to the doctors, but wanted some reassurance. Thanks.