Pain down low under belly on...?

For ages now I've had an ache belly between belly on and pubic hairline. This is a constant dull ache. I've got a 10 mth old who I'm always carrying on hip. Could this pain be due to that - its like a pain in my 'core' - if you see what I mean? Could it be my posture? I feed too, so always seem to be sitting awkward. What other symptoms should I look for if it was anything more sinister?????