Dog Shivering?

Katie • Wife and mother to two fur babies. Expecting baby #1, May 2016.

My coonhound does this weird shivering/twitching thing where she repeatedly tenses her muscles up in her front legs and chest. The shivers usually last for several minutes. I brought it up at her most recent vet appointment (February), and her vet wasn't concerned. She is otherwise healthy, very active, and does not seem to be bothered by the twitching. We keep our house quite warm, so it's not the cold. She eats a grain, corn, and soy free diet, so I doubt it is a food reaction.

Does anyone else's pup have a similar problem?

***Sorry if this is the wrong room. I was unsure where to post.