Yeah, I had this too about three weeks ago. I was kind of miserable and it was tough toting my 17 month old across the country for a trip! But doing stretches helped me immensely and I'm not even bothered by it anymore. Hope yours clears up and yes, talk to your doctor. :)
Hi there, I get this as well, went tl the doc and it is what is called Sciatica, it is a nerve in your lower back that is being pinched. There stretches you can do to try and release the nerve, but essentially the swelling needs to come down, so you need to look at how you are sleeping and sitting. Maybe you need some pillows in certain places to help support your back. If you weren't pregnant, the doctor would normally just prescribe an anti-inflammatory, but quite a few of these are not safe for the baby. Best to go to the doc and see what he/she recommends. Hope you feel better soon! Xx