Glad you are getting it seen too, especially the chest Xray - hopefully that will rule out walking pneumonia
I have pretty much exactly the same problem, but have now also lost my voice & sound like a seal when I cough - I was feeling rough already, breathless etc, but mine escalated after a sinus infection -
I took a course of antibiotics for it, but due to other health problems & being busy recently I didn't realise they hadn't worked properly, just dampened it down & when I stopped the anti Bs according to my GP the infection has spread & I now have a full blown respiratory infection - laryngitis, bronchitis, sinusitis & tonsillitis was just setting in
- my lungs apparently sounded clear, but I'm under strict instructions to go back for a chest Xray if the anti Bs don't seem to be working -
not sure yet, only my 3nd day - though I managed half the school run today - so a bit of an improvement, though voice & cough just as bad & boy do I feel for you with the chest hurting, that & my stomach muscles feel like I've been trampled on by an Elephant - like you say, I just couldn't manage the hill to School, but thankfully DD is old enough to do that bit alone, so I coped - DH had to stay home & do it the last 2 days.
I can recommend manuka honey for the cough - thanks to that I'm managing some sleep
& other than that, I wish you luck & feel for you - it sucks