Aw, yes normal yan sa pregnancy, lalo na ngayon na lumalaki na ang baby at umaasa ang weight sa lower back mo, a few of us mums experienced the same thing around that stage pa lang! The headaches can be related din sa hormonal changes and dehydration, so try to drink lots of water and rest when you can, pero since you're in your first pregnancy at gusto mong maging sure, best to mention both the back pain at headaches sa OB mo sa next check-up para ma-rule out kung may iba pang concerns at ma-advise ka properly on safe ways to manage them.