I had this regularly starting around 34 weeks, and it seem to get worst around 35-36 weeks. I also know from talking with others at the time who were in a similar gestation that they were experiencing it as well..
I did speak to my doctor about it to be safe, and was told that if it lasts more than an hour (even if its coming and going) and especially if its being accompanied by contractions then you should get checked at L&D because it can be a sign that labor has started but she said for the most part, it is not something to worry about
It can be. As you get further into pregnancy and the baby grows larger it puts more and more pressure on your lower body. Is it severe pain, or just mildly annoying? Are you having any contractions, or just BH. If you're unsure, never hesitate to give your doctor a call or go to L&D to be checked, but pain and discomfort as you get further along is generally expected.