Odd code at end of my url pages

https://www.tshirtsatfirstsite.com/shops/rockfirst-site/#.TuAYNGMr2so

I’m not sure if this is something I’ve created by accident. I just noticed it recently and there are times I click to enter my site but I get a 404 error.

Can any one tell wwhere this came from?

Thanks,
Donna

[No bumping, thank you.]