Safe muscle rubs?

Bekah • BFP 03.03.15 MC 04.07.15 BFP#2 04.08.16 -praying for our Rainbow; all while working in a daycare
Hey ladies (and gents) I just wanted to know if there are any baby/pregnancy safe muscle runs that I could possible find?  Or any other way to alleviate the pain?   
I have this major pain in between my shoulder blades and then in my lower back left hand side. 
My OH already gave me a huge relaxing massage but after spending a few hours at work it's already irritating and aggravating.
(I work in a daycare..continually picking up toys, children etc.)