Why can't I get a diagnosis? Shortness of Breath worsening

[Murdoc_OS]

I've been having shortness of breath 24/7 for over a year now can't seem to get a diagnosis. I'm only 24 and this is taking away my life.

The SoB is accompanied by heart palpitations (PVCs) and both get worse when standing from sitting, showering, and walking (especially up an incline).
Ive had lung function tests which showed a very minimal decline in flow which my doctor isn't worried about, along with blood work, a Holter monitor and even an echocardigram which all came back normal.
Its getting worse day by day and getting out of bed to go to work is a challenge as the SoB is also worse just after waking up.

The only other symptoms are a constant discomfort in my chest, like a pressure pushing outwards and up, but not inwards like angina pain or heart attack. I also wheeze on and off, but NEVER when my doctor listens to my breathing (which is distressing because it's like I can't prove that I'm in serious discomfort).

Inhalers don't work and anxiety meds did nothing but give me bad side effects. I'm at my wits end so I've turned here, again.
Thanks in advance for any help.