Itchy/tender rash on chest?

Savannah
I've had a red rash on part of my chest for a couple days now and it is very itchy and a little painful to the touch. I got a sunburn a few weeks ago and it's gone away now but it seems that the rash follows my tan line where my bikini top was. Could it be related? Does anyone else have the same issue? I emailed my midwife but she is out of town for a few more days, just hoping to get some opinions from you ladies! I've put aquafor on it for 2 days now and it isn't helping. :(
Also- I am 23 weeks pregnant!