Ache inner thighs?

Emma • Baby #1 - Boy 💙 born 14 July 2015!!
So I'm 27w5d pregnant and for a few weeks now every time I get up to walk my inner thighs at the top really ache. Only way I can describe it is that it feels like I've Bern sitting with my legs spread open for hours when they have been closed? Is it just me or is this normal? What causes the aches there? Thanks(learn more on Glow: https://glowing.com)