Cramping/tight feeling

Rose
So what I have noticed is if I walk a little faster or and normalish speed I get tighter expecially across my upper belly above belly button. Also noticing a cramp quite low. Not continual and not pattern but yesterday I was doing house work with breaks and the rest of the day I felt like I was paying for it. 
Are these simple stretching growing and changes happen or Braxton hicks or my body say slow the hell down? 
Anyone else having anything similar? Please share ladies :-) x