RASH NEXT TO ARMPIT, WHY? PHOTOS INCLUDED

This rash started to come up on Friday, I orginally thought it was due the shaving, however, the rash is everywhere on my armpit except where i've shaves/have hairs. It isn't itchy, however, it is sore/sensitive to the touch. Not sure cause or how to solve. My GP is full so getting an appointment can take a week. It seems harmless so just need quick diagnosis and cure.

If you are using any new products, you could be allergic to one or more of them.  Also, that area of the body is pretty sensitive.  If you use a scented body spray, it could be the culprit.  I have had that happen before from scented body sprays.  I keep using them anyway because I love them! (LOL)

Could be! I will get roll on and then if/when it goes away, I will spray again like you haha

As TXOAP says it could be an allergy. I should stop using any under arm product short term and see if it improves.

Agree - stop using everything except water on your skin for a week or so, then gradually reintroduce products to identify what's causing it (e.g. preservatives in the anti-perspirant?)