Rash of Unknown Origin, Mystery Continues

I've had a rash type situation on my chest and neck that makes it itchy, sore, burn, red, hot and generally be unpleasant for about a month.  It waxes and wanes, but it never fully went away after it started.  I changed sunscreens not long before the problem started happening, but I didn't make the connection.  At times it felt like a sunburn, and the redness is really making it look like I've gotten sun somehow.

I finally have mostly decided that it must be the sunscreen.  I have been using Neutrogena dry touch Helioplex products (on my face I have been using the ultra sheer liquid for a couple months maybe).  Prior to this, I was using a CVS knock-off of the dry touch stuff.  Today my face was burning for at least 3-4 hours after applying the sunscreen, along with my neck.  I had cut down to using just the sheer liquid since I hadn't had issues in the past, I'm really starting to wonder if I've developed a sensitivity to it.

So, I walked over to Walgreens this evening and picked up the most sensitive skin-physical only sunscreen I could find.  There weren't a lot of options, most things include chemical sunscreens.  I found a Walgreens branded sensitive skin, oil free, non-comedogenic, PABA free, fragrance free - you name it, doesn't have it - sunscreen.  It smells pretty gross.  But if I can stay protected from the sun without having inflamed skin, I think I can learn to put up with it!  The only active ingredients are zinc and titanium dioxide.  We'll see how it applies, if it's too gloppy to tolerate, if it leaves me greasy, if the smell dries me batty, etc.