Try stretching every morning and night, it will loosen your back up. Maybe look into yoga or pilates, those could help too.
I am experiencing the same issues since entering the 5th month of pregnancy. I see a chiropractor that specializes in prenatal chiro care, they will assess you and provide a plan of action. Depending on the severity of the pain, it may take weeks to feel 100%. For my case, it took 3 weeks of chiro care.