Constant dull ache in back while pregnant. what can i take for this?

Heating pad: I am aware that this is uncomfortable, however as the shape of the spine changes with advancing pregnancy there can be some discomfort. What you don't want to do is impair your developing fetus by adding continuing analgesics or opioids which can cause medical issues. Try a heating paid on the area or a warm bath, as like most things, this ache is temporary.