hey leasha, i get a very similar thing, it seems to happen when i am sitting in an un comfy position and i go all tight until i stretch and then it settles, but is easily cramped again!! I get it bad when driving and sitting at my lap top when im not at the desk (naughty me)
it scared me abit and when i mentioned it to the mid wife she said maybe BH, but that at 14 weeks its a bit early.

I find laying on my back helps and stretching abit.

xoxo