Ay oo, normal lang yan sa pregnancy, lalo na pag lumalaki na ang baby! A few of us moms dito sa group namin nag-complain din ng back pain kahit 3-4 months pa lang, kaya don't worry too much. The thing is, when you get further along, it tends to get worse dahil sa weight and posture, so it's good na nag-start ka na ng stretching or prenatal exercises if kaya mo. But since it comes and goes, best to mention it sa OB mo sa next checkup, para sigurado na walang iba pang issue at sigurado ka lang talaga, better safe than sorry, di ba?