Aw mama, first trimester back pain is real, I had it too kaya I totally get it! The best thing that helped me was proper posture (yun ang mahirap lagi hehe) and wearing a pregnancy support belt, plus stretching gently every morning, pero honestly the safest route is to check with your OB na para makasiguro kung normal lang ito or may kailangan i-address. A few of us moms also swear by prenatal massage or just asking our partners for shoulder rubs, sobrang sulit!