Cramps in early pregnancy

Kerri • 17 months ttc, 4 cycles fertility treatments just got my + hpt today!!!
4w4d today. This is my second pregnancy. But my son is 3 years old and I don't remember what it was like! Is it normal to have a little dull cramping and backache every now and then? Last night when I laid down for bed I was experiencing this. But I was also outside doing yardwork most of the day so that could have contributed....?