Hi, any advice or experience appreciated... I'm just 4 weeks pregnant but the past 2 days my lower back is ridiculously painful. If feels muscular I think and a bit like a harsh version of what I get before and during period. I don't have any other cramping or bleeding I'm worried about at the moment, but am in real pain. I just hope it's not a bad omen and a common symptom I suppose. Any thoughts?