If it comes and goes quick it is Brenton hicks if it doesn't go away quick it might be because the baby favors one side more then other and that puts a lot of pressure on the mussels. I just learned that from my doctor couple weeks ago because I had crazy cramps in the same spot. I hope it helps. If you really worried about it you should call your doctor in the morning just for piece of mind

@secondtimemomtobe, 35 weeks on Wednesday

Sounds like BH

How far along are you?