Hi! The short answer is yes. During the 3rd trimester of pregnancy, your body produces a hormone called relaxin, which allows ligaments to stretch in your pelvis to get ready for the passage of your baby through the birth canal. That’s a good thing, but it also relaxes other ligaments—in your lower back—and the baby’s weight causes increased lumbar lordosis (A-P curvature concave anteriorly in the lumbar spine for you anatomists) in YOU. This, in turn, causes shortening of your lumbosacral paraspinal muscles (including the short and tightly bound multifidi muscles) and increased eccentric load on lumbar spinal extensor muscles. In short, a lot more pressure on your low back that can kead to pain. There is often microscopic tearing, a.k.a. muscle “strain” in those muscles, typically pain OVER the sacrum, sacroiliac joint (not IN the joint), and aling the spinous processes where those muscles attach. This pain can last beyond the birth of your baby, of course.
See a chiropractic physician who can teach you therapeutic exercise for whatever diagnosis you have. Good luck and feel better!