Back Pain

Has anyone experienced back pain? I'm only 11+6 but my very lower back is very painful. I'm otherwise fit and healthy (apart from constipation) and have not put on much weight and so I find it hard to believe it's pregnancy related? I don't want to go to my Drs and have him be like - duh, pregnancy! But I'd say the pain is 6/10 which seems extreme at not even 12 weeks? Wld love to hear thoughts / experiences. Thanks in advance.