Lower Back Pain

Goodmorning mommies and soon to be. It's my first pregnancy. I'm in my 4th week now (based on my calculations (first day of last mens - 17 Jun 2019)) and I haven't talked to my OB yet kasi ang schedule nya dito sa clinic near us is on Monday pa. I'm 3 days delayed, took my PT and it's positive so I called my OB immediately and she confirmed that yes I'm preggy.. My question is, is it normal to have a back pain around this time of pregnancy? Thank you so much! Ps: photo of the PT result attached. Please check it also if it's positive. Tho my OB confirmed it.. Thank you..