You are putting on a load forcing the lower back to bend more to the front and the ligaments are stretched and hurt. But, there is even more. The womb, the baby's current home, is fastened to the middle of the lower back with a very strong, thick ligament. As baby gets bigger and heavier, it pulls on that ligament more and more. It forces Mama's back to bend forward more and more.
Nature has a cure.
Using muscles Mother Nature provided, you may be able to straighten out your back, taking the load off the ligaments. In so doing, the muscles on your stomach contract, carrying the load of baby. Also, in so doing, your back is prepared to absorb shocks, just as your neck is in the demonstration we did with your hand and index finger. It took me 3 months to find them - even though they were right there all along. I just had to discover how they work.