Each month from day 1 of my period until day 5 I have a dull ache in the same spot each cycle in my abdomen when moving or bending, about where my uterus would be. It only occurs when my period arrives and vanishes when it ends. This started for me about 1 year ago. Could it be endometriosis? Does this happen to anyone else? I also have heavy periods for 3 out of the 5 days and spotting for an additional 4 days after my period has ended.