Ladies help me out with this! Lower back pain

Ju

With my first pregnancy during the third trimester I would get a pinching pain on the left side of my lower back. It would shoot down all my leg and make it virtually impossible to walk on. It would happen periodically and go away on its own.

Dr said the baby would be on a nerve causing the pain.

I'm 14 weeks along now with the same pain, it's too early for the Baby to be on a nerve right?!

What the heck could this be?!