i am 15 weeks pregnant... frm 2 days i m feeling slight pain in lower abdomen mostly in evening... what is the reason for this..?

Lower abdomen pain if it is like cramps which come and go must be checked by the doctor. It is normal to feel a stretching kind of feel which can be mildly uncomfortable as you enter the second trimester as the uterus is now stretching and extending out of the pelvic cavity.