Sharp/painful cramp in lower right abdomen in the 2nd trimester

I am 20 weeks and while laying down with my son I suddenly got a very sharp and painful cramp on the right side of my abdomen. It felt different than the usual round ligament pain, I had to stand up quickly but nothing helped. It lasted about a minute and has been gone since, my abdomen just feels sore almost (not he best word to describe it, kind of gassy). Anyone else have this or know what it could be? I feel baby kicking, it's just making me a little worried.