Yes, back pain is very common in early pregnancy as the body starts adjusting. Try using a small cushion behind your back when sitting, and take plenty of rest.
Our bodies undergo so many changes to bring a new soul into the world, so some aches are natural. Just stay positive, do simple prayers, and take proper rest.
I am hoping to conceive soon, but my cousin told me her backache started almost immediately in the first month. It seems to be a very common early sign.
I had bad back pain early on, and my mother-in-law advised me to avoid sitting cross-legged on the floor and to use a warm compress. It actually worked wonders!
I am in my 2nd trimester now, but my back pain started really early, around week 6. Did anyone else experience this so early, or did it only start later for you?