itchy skin/pregnancy related?

Ok.. so when I found out I was pregnant I started using coconut oil on my body as a moisturizer bc it's natural and bc I've heard it's good for stretching skin in pregnancy. I also had a HUGE tub of it. I don't know if it's the coconut oil irritating me or if it's pregnancy related but... my skin has been itchy but it's alwaya MY BACK. I notice it bad when I'm in the shower and later at night, after I've applied the coconut oil. Last night I stretched and finally decided to check it out in the mirror and it was red and Welped up. I know your backs a tricky area so I make sure to wash it, rinse it, and moisturize it well. Surely coconut oil wouldn't irritate? Anyone else have this issue with pregnancy?