I'm 21, female, about 5'7 and 110 pounds and have never had any health problems. I just want to inquire about a tightness in my abdomen that I sometimes get less than a week before I start my period. It's sort of a mix between a feeling of tightness and a cramp and the area is right at my belly button to right below it in my lower abdomen. I will be sitting slouched, or curled on a couch or bed, and if I sit up and straighten out and stretch, the tightness can be pretty painful. Its not as bad if I stretch back out gradually. This only happens a few days before I start my period, and it doesn't happen every period. I started my period when I was 14 and have never had any issues with it, no cramping or PMS, its always been regular, and I have never been pregnant.